







How many lines of symmetry does a circle have? 
20190528 

From raji: how many lines of symmetry does a circle have??? Answered by Penny Nom. 





Parallel and Perpendicular lines 
20170717 

From Karen: Find an equation for the line with the given properties. Perpendicular to the line 7x + 2y = 6; containing the point (2, 1)
Find an equation for the line with the given properties. Parallel to the line 5x  3y =6; x intercept = 3 Answered by Penny Nom. 





Two wires between two buildings 
20170511 

From Bill: I need to find the height of the intersection point of two building wires< br />
Building A is 860 feet high and building B is 480 feet high. The wires existent from the top of one building to
The bottom of the other < br />
The distance between is 32 feet Answered by Penny Nom. 





Parallel lines 
20161026 

From Jordan: (7,5) 3x 4y=5 Answered by Penny Nom. 





Perpendicular lines 
20160214 

From Brendon: points A (4; 6) , B (1;2), C (5;3) and D (4; 1) are given
prove that AC and BD are perpendicular to each other Answered by Penny Nom. 





A region defined by three lines 
20150316 

From Lucinda: find the area of the figure formed by the line y=5x+9 and the xaxis and yaxis. Answered by Penny Nom. 





Two regression lines 
20140614 

From catherine: Given a set of data values ,we can get two regression lines .Explain. Answered by Robert Dawson and Penny Nom. 





A question concerning two lines 
20140509 

From Hela: The equation of the line L is 6x+5y=3, and the equation of line Q is 5x6y=0, which statement below about the line is true?
A) same y intercept
B)parallel
C) Same x intercept
D)perpendicular Answered by Penny Nom. 





A circle which is tangent to two perpendicular lines 
20140309 

From MJ: I'm a College Student taking up Bachelor of Secondary Education on Math Subject.
And I'm struggling for my research about Circles. I done solving the said topic particularly on this question:
"What are the possible equations of a circle being tangent to a pair of perpendicular lines, having the origin as the Point of Intersection and the C (h, k), where h, k ∈ℤ"
But I can't get what would be the process that I must do in order to jive to my idea/goal for that problem.
Please check my idea that the numerical coefficients of the equation is equal to the radius of the circle.
Thanks in advance! :) Answered by Penny Nom. 





Two perpendicular lines 
20130815 

From Hanna: The problem says, "Write the equation in standard form for the line that is perpendicular to the graph of y=5x+1 with a yintercept of 4." I have no clue how to do this. Please help me! Answered by Penny Nom. 





The distance between 2 lines in 4D 
20130401 

From samane: how can i measure the distance between 2 lines in 4D?? Answered by Chris Fisher. 





Tangents to the curve y = x^3 
20130324 

From Ethan: How many tangent lines to the curve y = x^33 pass through the
point (2, 4)? For each such line, and the exact coordinates of the point of
tangency on the curve. Answered by Penny Nom. 





An equilateral triangle and some circles 
20120110 

From tushar: draw an equilateral triangle with side 6cm.draw 3circles with radii 3cm on each angular point of triangle.draw common tangent on each of two circles Answered by Penny Nom. 





Lines tangent to y^2=4x 
20111111 

From Reuchen: Find equations of the lines tangent to y^2=4x and containing (2,1). Answered by Penny Nom. 





A transversal 
20110330 

From Jillian: I don't understand finding angels in a transversal Answered by Penny Nom. 





Exactly two lines of symmetry 
20100411 

From debbie: i am looking for a quadrilateral with exactly two lines of symmetry. please help! thank you. Answered by Tyler Wood. 





A system of equations 
20100330 

From samantha: the equations of two lines are 6xy=4 and y=4x +2.what is the value of x in the solution for this system of equations? Answered by Penny Nom. 





The angle of intersection between two lines 
20100325 

From Madhumitha: How to find the angle of intersection between a line x=249 and another line which is of the form y=m*x+c; Line1 has a slope of infinity so what does the angle of intersection turn out to be? Or how can i find it? Answered by Chris Fisher. 





The acute angle formed by intersecting lines 
20091217 

From Katie: To the nearest tenth of a degree, find the size of the acute angle formed by the intersecting lines 3x + 2y = 12 and x  2y = 2. Was is necessary to find the intersection point? Answered by Robert Dawson. 





The point of intersection of the pair of straight lines 
20091119 

From Stephanie: Find the point of intersection of the pair of straight lines:
y=3x9
y=4x+2
x = _______ and y = ________
I am totally confused. Please help Answered by Robert Dawson. 





The intersection of two graphs 
20091030 

From asma: by using the suitable scales,draw both the graph of x/2 + y/4 =3 and y=2 on the same graph paper.Find the points of intersection of the two graph. Answered by Penny Nom. 





Is it a rectangle? 
20091029 

From sefora: The coordinates of the vertices of quadrilaterals are given.
Draw each quadrilateral on a grid.
Determine whether it is a rectangle (show your work)
P(5,1), Q(4,4), R(6,2), S(3,5) Answered by Penny Nom. 





Forming a square 
20091021 

From christianah: Two parallel lines have the equations y=x+4 and y=x2.Two additional lines are drawn to form a square.What is the side length of the square?Write possible equations for the additional lines.Explain and justify your reasoning. Answered by Penny Nom. 





Parallel lines 
20090701 

From chris: Write the slope of a line that is parallel to each line.
1.y=2x5
2.y=x+2
3.3x+y=10
4.5xy=11
5.x+2y=6
6.2x3y=9
7.4x+y=3
8.x+2y=14 Answered by Brennan Yaremko. 





The product of gradients between 2 perpendiculars lines 
20090611 

From Alister: how do i prove that the product of gradients between 2 perpendiculars lines equal to 1.... Answered by Penny Nom. 





Perpendicular lines 
20090507 

From shabnam: the line presented by y= 3x2 and a line perpendicular to it intersect at R(1,1). Determine the equation of the perpendicular line Answered by Stephen La Rocque. 





Parallel and perpendicular lines 
20090408 

From Blake: I need to know what the formula for working a problem. I need to know how to find if i line is parallel or perpendicular by only looking at the equation. i know you must know the slope but how do i find slope? Answered by Stephen La Rocque. 





Are these lines parallel? 
20090206 

From Conor: are these lines parallel?
y = 3x 2 and 6y = 3x +2 Answered by Stephen La Rocque. 





The intersection of two lines 
20090130 

From kaylee: how do you find and graph the intersect of these two equations:
y=2x4 (and) 2y=x
thanks,
kaylee Answered by Stephen La Rocque. 





The point of intersection of the straight lines 
20090118 

From Kieran: Find the point of intersection of the straight lines
y=2x+4, and y+2x16=0 Answered by Robert Dawson and Penny Nom. 





A line is perpendicular to another line 
20090116 

From Greg: A line is perpendicular to the line y=2x+3 and has the same xintercept as x+3y+10.
Find the equation of this line. Express your answer in the form of y=mx+b. Justify your answer. Answered by Robert Dawson. 





The angle between two lines 
20081217 

From abhi: how to calculate the angle between two lines, given the length of the lines..
angle should vary from 0  360 in the counterclockwise direction Answered by Robert Dawson and Harley Weston. 





The sides of a rectangle 
20081208 

From Mitchell: The perimeter of rectangle ABCD (represented on a Cartesian plane) is 52cm.
The equation associated with segment AD is 3x+4y60=0
Point C is at (18, 14).
What is the length of segment AD? Answered by Penny Nom. 





A geometric construction 
20081017 

From M: Given any 3 parallel lines on a plane, how to construct an equilateral triangle with each vertex on each line? Answered by Chris Fisher. 





Perpendicular lines 
20081016 

From Hailey: In the xyplane,
the line with equation 2x + y = 3
is perpendicular to the line with equation y = mx + b,
where m and b are constants.
What is the value of m? Answered by Penny Nom. 





Lines that pass through a point 
20080930 

From Abigail: what is the name for a point that a group of lines pass through that contains the letters c e n p i l? Answered by Penny Nom. 





5 units from (1,2) and 5 units from yaxis 
20080926 

From Shaun: Find the points (x,y) in the plane that are 5 units from (1,2) and 5 units from yaxis.
I am more interested in the approach, in general terms, than the numerical values. Answered by Penny Nom. 





Parallel and perpendicular lines 
20080906 

From C: Can you help me determine whether these lines are parallel, perpendicular or neither and why?
Problem 1: y=3x+2
y=1/3x  4
Problem 2: y=1/3x + 1/2
y=1/3 x 2 Answered by Penny Nom. 





Joining vertices in a polygon 
20080818 

From Megan: I'm trying to develop a relationship between the number of points of a regular polygon and the
(a) number of lines you could draw between those points,
(b) number of triangles you could draw,
(c) number of quadrilaterals,
etc. Answered by Penny Nom. 





Overbooking flights 
20080710 

From DON: Overbooking by Airlines
This is a simplified version of calculations used by airlines when they overbook
flights. They realize that a certain percentage of ticketed passengers will cancel
at the last minute. Therefore, to avoid empty seats, they sell more tickets than
there are seats, hoping that just about the right number of passengers show up.
We will assume that the noshow rate is five percent.
For a flight with 220 seats, the airline wants to find how sensitive various
probabilities are to the number of tickets it issues. In particular, it wants to
calculate
a) the probability that more than 225 passengers show up
b) the probability that more than 220 passengers show up
c) the probability that at least 215 seats will be filled
d) the probability that at least 210 seats will be filled.
To assess the benefits and drawbacks of issuing various numbers of tickets on an
airline flight with 220 seats, create a table showing as many different scenarios
as possible (table only on one page when printed) and use a second page for
your analysis and recommendation to the airline. Which are the good cases,
which are the bad cases for the airline? Answered by Janice Cotcher. 





Straight lines 
20071126 

From Divyansh: hello
i am in eleventh class and am, preparing a project on straight lines
i cant really find uses of straight lines and its equations in daily life
i am also thankful to you in advance and am waiting for your answer eagerly because i need to submit my project only this week
thanking you Answered by Penny Nom. 





Two lines 
20071118 

From Kate: represent qraphically the equations of these lines and their intersecting points
xy=2
3x+y=11 Answered by Penny Nom. 





Finding equations, intersection point of two lines at right angles 
20070922 

From Yaz: Find the equation of the line joining A(1,9) to B(6,120). Another line passes through C(7,5) and meets AB at rigth angle of D. Find the euation of CD and calculate the coordinates of D. Answered by Stephen La Rocque. 





Perpendicular lines 
20070906 

From dinesh: we know that for two perpendicular lines
m1*m2=1perpendicular
but this is not true for xaxis and yaxis? Answered by Harley Weston. 





Twocolumn proof for a circle geometry problem 
20070824 

From Kendra: i have to prove that tangents to a circle at the endpoints of a diatmeter are parallel by stating whats given, whats to prove and a plane, then write a two column proof i dont understand this Answered by Stephen La Rocque. 





Two coplanar lines 
20070821 

From Robin: I am going two show that the two lines are coplanar:
(x5)/4=(y7)/4=(z+3)/5
(x8)/7=y4=(z5)/3
I know I have to find a point that lie on both lines, but dont really get it. Answered by Stephen La Rocque and Penny Nom. 





Proving a quadrilateral is a rectangle 
20070714 

From Sonja: I was having this discussion with another teacher and we need a third opinion. When you are trying to prove a quadrilateral is a rectangle which method should you use:
 Prove the shape is a parallelogram by doing slope 4 times by stating that parallel lines have equal slopes. Then proving a right angle by stating that perpendicular lines have negative reciprocal slopes.
 Doing the slope 4 times and stating that the shape is a rectangle because opposite sides are parallel because of equal slopes and it contains a right angle because of negative reciprocal slopes.
I guess the real question is do you have to first state that the shape is a parallelogram? Answered by Stephen La Rocque. 





Two tangent lines to y=x^3 
20070607 

From stephanie: find the equations of two tangent lines to the y=x^3 function through the point (2,8) Answered by Penny Nom. 





The distance between parallel lines 
20070528 

From Kristie: I can't figure out how to determine the distance between parallel lines I am taking
linear algebra and vector geometry. I was given two lines in the form #x+#y =#
told they were parallel and asked to find the distance between them??
Please help
Thanks Answered by Penny Nom. 





Slicing a doublenapped cone with a plane 
20070507 

From Andrew: I am writing a paper about creating parallel lines by slicing a doublenapped cone with a plane. I have found out how it can be shown by algebra that the equations for parallel lines are generated from the degenerate case of a second degree polynomial in two variables, but I have yet to find a source with a visual representation of this case. Do you know if it exists? Answered by Chris Fisher. 





Finding out if two line equations are parallel or perpendicular 
20070428 

From Vincent: Can you determine if the two lines are parallel, perpendicular, or neither
1/2x+4y=3/5
y/1 + 10/5= 8x
I think there perpendicular but how would you solve the equations Answered by Stephen La Rocque. 





A line parallel to a given line 
20070428 

From vince: write an equation of the line satisfying the given conditions
Through (2,3) parallel to 2x=3y+5 and graph both equations Answered by Penny Nom. 





A line parallel to a given line 
20070426 

From vincent: I forgot how to write the equation of the line satisfying the given conditions
through (2,3) parallel to 2x=3y+5
and how would you graph this Answered by Penny Nom. 





Two parallel lines 
20070425 

From prasanna: Let me know the Equation of a line which is parallel to some other line at a distance of Dmts. Answered by Penny Nom. 





Two lines intersect at a right angle 
20070420 

From ellen: The line with the equation 3x + by = 6 intersects with the line 6y + ax = c at right angles at the point
(4,6). Determine the values of a, b & c. Answered by Stephen La Rocque. 





Slopes of perpendicular lines 
20070327 

From Mykolyn: How do you find the slope of a line that is perpendicular to the graph of:
y= 1/2x+4? Answered by Leeanne Boehm and Sara Ulmer. 





A line that is perpendicular to another line 
20070316 

From Jesse: How do you write an equation of a line that is perpendicular to
y+2x+3 and passes through (3,4); I don't understand the steps
of how to do this???? Answered by Stephen La Rocque and Penny Nom. 





Prove that the triangle ABC is isosceles 
20070305 

From Lisa: I am stuck on this problem... If AB = CD (parellel line), and Answered by Stephen La Rocque and Penny Nom. 





The intersection of two lines 
20070228 

From Tamara: I was told to make a graph to help solve this question. I was given two equations. One was x2y=3 and the other was 2x+y=4. We have to change it to the equation of the line format. Then we graph the line and find the point where they meet. I've been trying to do that, but when i check the answer, It turns out wrong. It's meeting in the wrong spot. I need help please. Answered by Penny Nom. 





Parallel lines 
20070227 

From Jennifer: How to you decide whether the graphs of these two equations are parallel linse: y=3x+2, y=1/3x+4 Answered by Stephen La Rocque and Penny Nom. 





A line perpendicular to another line 
20070113 

From Dusty: Find an equation for the line perpendicular to: 3x  4y + 1 = 0 passing through (4,7) Answered by Leeanne Boehm and Penny Nom. 





Family of lines 
20060929 

From Sasha: could a "Family of Lines" have both parallel and intersecting equations that aren't related directly but otherwise related by each other to create a curve Answered by Chris Fisher. 





Rays 
20060831 

From Natasha and daughter: My daughter, Natasha, is in 4th grade. She had the following homework question about rays that confused us:
Name as many rays as you can in the figure below. Answered by Penny Nom. 





An angle in a parallelogram 
20060813 

From Sam: Parallelogram ABCD has diagonal AC equal in length to side AB. CD is produced to E so that D is between E and C. If angle BAC =30 degrees find the size of angle ADE. Answered by Stephen La Rocque. 





Equations of two lines 
20060405 

From Wael: Determine a cartesian equation of the line passing through A and V as a direction vector?
1 A (2;1) and V = j
2 A (2;3) and V = i Answered by Penny Nom. 





Two parallel lines 
20060122 

From Marbara: On my math homework I have a problem where it says find the value of x so that L is parallel to M
on one of the there are three lines. the top one is horizontal which is L. the bottom one is also horizontal directly under L which is M. there is another line that is diagonal going through the middle sections of L and M.
To the right of the diagonal line and right under line L is an equation 5x10
to the right of the diagonal line and right above line M is an equation 8X5
I tried to find what X is but I can't because it never matches both equations no matter what way I try to do it. Answered by Penny Nom. 





What is the angle between 2 noncollinear parallel lines? 
20051017 

From Ben: What is the angle (if any) between 2 noncollinear parallel lines? Answered by Chris Fisher and Walter Whiteley. 





Two intersecting lines 
20041218 

From James: Imagine a vertical line 1.107' tall. Leaving the top of this line, sloping down to the right at a 4:1, at what horizontal distance will the line strike a second line, which leaves the the bottom of the vertical line sloping down to the right at a rate of .02 ft/ft (or 2%)? There is a fairly easy solution to this, but I have lost my notes! Answered by Harley Weston. 





A theorem involving a trapezoid 
20040929 

From Abraham: Given:Trapezoid ROSE with diagonals RS and EO intersecting at point M
Prove:Diagonals RS and EO do not bisect each other. Answered by Harley Weston. 





Graphing lines 
20040208 

From A student: how do you solve y=1\3x+3 and y=1\3x3 by graphing? Answered by Penny Nom. 





Intersecting a line and a curve 
20040129 

From Senthil: between line and curve how can i
find intersection point?
could you write me the formula and explanation also sir. Answered by Penny Nom. 





Lines 
20031114 

From A student: What is a name that a group of lines pass through? Answered by Chris Fisher. 





Intercepts 
20031104 

From A student: I am totally confused on how to determine intercepts of an equation and then to graph the line. For example, how to determine the intercepts of 2x3y12=0. Answered by Penny Nom. 





Squares in a rectangle 
20031021 

From Raj:
Draw a rectangle with sides of 3 and 4. Divide the sides into 3 and 4 equal parts respectively. Draw squares joining the points on the sides of the rectangle. You will have 12 small squares inside the 3 x 4 rectangle. If you draw a diagonal of the rectangle, it will intersect 6 of the the 12 smaller squares. Similarly, if you have a 4 x 10 rectangle, the diagonal would intersect 12 of the 40 squares inside the rectangle. Is there an algebric equation that determines the number of squares that will be intersected by the diagonal of a rectangle? Answered by Chris Fisher. 





Two line segments and a plane 
20030911 

From Laura: Do all figures made up of two segments lie in a plane? Answered by Penny Nom. 





Collinear Points 
20030113 

From Gary:
Which of the 4 points are collinear when you construct the following concurrent lines or rays of a triangle?  P(1), the point where the angle bisectors intersect.
 P(2), the point where the altitudes (or extensions) intersect (inside or outside of the triangle).
 P(3), the point where the medians intersect.
 P(4), the point where the perpendicular bisectors (or extensions) of the three sides of a triangle intersect.
This is for my 912 high school class in geometry. My name is Gary Thanks for your help. Gary
Answered by Harley Weston and Chris Fisher. 





Parallelograms 
20020821 

From Moorthy: 11 parallel lines are intersected by another 9 parallel lines.Then how many parallelograms are formed? Answered by Walter Whiteley. 





Lines of symmetry 
20020422 

From Cindie: How many lines of symmetry do the following figures contain? trapezoid: rhombus: hexagon: pentagon: Answered by Walter Whiteley. 





A 1 m by 1 m square box in the xyplane 
20011215 

From Murray: Inside a 1 m by 1 m square box in the xyplane, there are finitely many line segments, whose lengths sum to exactly 10 m. Show that there exists a straight line in the plane which crosses at least six of these line segments. (Hint: first, show that there exists a straight line in the plane which crosses at least five of these line segments.) Answered by Claude Tardif. 





Normal lines 
20011211 

From Kristie: Why are perpendicular lines called normal lines? Answered by Chris Fisher. 





Lines in the plane 
20011021 

From Greg:
*If the line with equation 3x4ky= 16 has yintercept 2, find k. *Write the equation of the line passing through (2,5) and perpendicular to the line passing through (2,4) and (6,1) Answered by Penny Nom. 





Where do the lines y=2x4 and y=x1 intesect? 
20010406 

From Bryce: solve the following problem by setting them equal to each other. Solve for x and y. Where do the lines y=2x4 and y=x1 intesect? Answered by Penny Nom. 





Linear equations 
20010213 

From Jamie: I have a question how do you do linear equation? Answered by Penny Nom. 





Kinds of lines 
20010209 

From Robyn: What are the different kinds/types of lines? Answered by Leeanne Boehm. 





Connecting to a water line 
20001020 

From Vanja: My question is...A house is to be connected to a new water main that runs along the line y=2/3x1. The connection point at the house has coordinates (2,9), where the units represent metres. What lenght of plastic pipe is needed to connect to the water main at the closest point? Answered by Penny Nom. 





How many planes contain a line and a point? 
20000830 

From Harold: How many planes contain each line and point? Answered by Harley Weston. 





Lines on an oscilloscope screen 
20000620 

From Janis Watson: What are the proper names for the vertical and horizontal lines on a graph? I am trying to explain an oscilloscope screen, and I don't know what to call these, except "vertical lines" and "horizontal lines." Answered by Penny Nom. 





Parallel and perpendicular lines 
20000508 

From Jimmy Lumpkins: Need a method for solving the following problem: Find the equation of a line through point P that is parallel or perpendicular to another line. Answered by Paul Betts. 





Angle of Intersection of Two Lines 
20000302 

From Veronica Patterson: I am having a real hard time trying to figure out this problem. Could you please help me! The homework question says to find the acute angle of intersection between the two lines y=3x+1 and y=(1/2)x1. (It also says to use the results of a problem I had already figured out.) That problem was to use information from a picture shown that tan(theta sub1theta sub2)= ((m sub2 m sub1)/(1+(m sub1 * m sub2))). I used the difference identity of tangent to figure out the answer. Any help on this problem would be greatly appreciated. Answered by Harley Weston. 





Parallel lines 
20000112 

From Lori: Find an equation of the line parallel to the given line containing the given point. x + y = 2; (1,2) We know parallel line have the same slope and we know the answer y = x + 3. Answered by Penny Nom. 





Parallel planes 
20000110 

From Hugo Alvarez: When two parallel planes are cut by a third plane, the lines of the intersection are? Answered by Claude Tardif. 





Slopes of curved lines 
19990609 

From Stephen Ehrler: When one plots the graphs of y=2^{x}, y=3^{x}, y=x^{x} When each of these graphs pass through point (0,1) do they have the same slope? I know they are different lines but is it possable that they have the same slope at point (0,1). Answered by Harley Weston. 





Parallel and perpendicular lines 
19990423 

From Crystal Pilling: My name is Crystal Pilling and I am in 9th grade algebra. We are currently studying parallel and perpendicular lines. I am having trouble with this problem: 3/4x  5y= 16, (5,6) I have to find a line that is perpindicular to this line on a graph. HELP ME PLEASE!!!!! Answered by Penny Nom. 





Dividing a Circle 
19990412 

From Mike Kenedy: I am having trouble with a homework question for bonus marks. A Circle is continually divided by lines that do not intersect the center so that they produce the most pieces of circle. For example  1 line divides the circle into 2.
 2 into 4.
 3, however into 7.
 4 into11
 5 into 16
 6 into 22
 7 into 29
 8 into 37
 etc...
I am stumped and cannot figure out the equation, though I'm sure it involves squares. Can you help? Answered by Penny Nom. 





Intersection of Planes 
19981203 

From Lindsay Fear: My name is Lindsay Fear. I am an OAC student (which is the Ontario equivalent to Grade 12 in most other states and provinces). I am in an Algebra and Geometry course and am currently studying a unit on equations of planes. Our teacher has given us this question that my friend and I have attempted several times, but we are still unable to solve it. My teacher has also suggested using the internet as a resource. The question is: Prove that a necessary condition that the three planes x + ay + bz = 0 ax  y + cz = 0 bx + cy  z = 0 have a line in common is that a^2 + b^2 + c^2 + 2abc = 1 Answered by Walter Whiteley. 





Intersection of planes 
19981122 

From Dave Rasmussen: I am a teacher of secondary mathematics with a question about the uses of Three Dimensional Coordinate Geometry. I have been teaching my students to write equations of planes and lines,  to find the intersection of these and the distance between them. What I am having difficulty finding are good applications of these techniques to "real world" situations. Can anybody help me? Answered by Walter Whiteley and Harley Weston. 





Concurrent Lines in a Triangle 
19980810 

From Chris Woolf: The question is Name four types of concurrent lines, rays, or segments that are associated with triangles. Answered by Chris Fisher. 





Graph question 
19980512 

From Rose Seminary: Why is the point of intersection of two lines the solution to the corresponding system of equations? Answered by Penny Nom. 





Yintercept 
19980227 

From Don Trumpet: What is the Yintercept for the problem:Y = 2(x+2) + 9 Answered by Harley Weston. 





Intersecting Lines. 
19980210 

From Erik Heppler: My typewriter frequently makes mistakes. Suppose I gave you the following system of equations to solve: 35.26X + 14.95Y = 28.35 187.3X + 79.43Y = 83.29 When I looked back, I realized that I meant to use 14.96 as the "Y" coefficient in the first equation instead of 14.95. Solving the system using 14.95 and then solving another system using 14.96 with all other values the same both times results in the intersection points (1776, 4186) and (770, 1816) respectively. How can that be? Answered by Penny nom. 





Calculating the Intersection Point. 
19971210 

From Milton Parsons: Given 2 lines through (x1,y1),(x2,y2),and (x3,y3),(x4,y4). Can you give me a good formula for calculating the intersection point. I would greatly appreciate it.Thanks. Answered by Chris Fisher and Penny Nom. 





How many intersections? 
19971008 

From James: (a) A collection of eight points, no three collinear. If lines are drawn between each pair of these points, how many points of intersection would there be? (b) what would your answer have been in part (a) if there had been n points to start with? Answered by Chris Fisher. 





Equation of a line 
19970408 

From Susan Gregson: I am a secondary school teacher. My students and I would like to know why the letters m and b are traditionally used to stand for slope and Yintercept in the standard form of an equation. Was this an arbitrary choice? Who made it? Are the letters from Greek ot Latin words? Answered by Harley Weston. 





Prove that these two lines are parallel. 
19960529 

From Adam Piekarzewski: Using parallel line theorems and side angle side etc. in triangle acd a line is drawn from point b on ac and point i on ad. another triangle fliped vertically and joined at d is named fdh, a line is drawn from point e on fd and point g on fh. ab = fg, ai = fe, ac  fh prove that bi  eg / / Answered by Harley Weston. 

