







The distance between the origin and a moving point on a graph 
20171016 

From Paulina: Find the rate of change of the distance between the origin and a moving point on the graph of y=x^2 +1 if dx/dt=2 centimeters per second Answered by Penny Nom. 





Long division with decimals 
20170616 

From Kenneth: Hello:
Why is it recommended to move the decimal from a divisor when dividing so that the divisor is a whole number?
I know how to divide by moving the decimal from the divisor, but I cannot explain the reason.
I thank you for your reply. Answered by Penny Nom. 





Two pieces of rope 
20160521 

From Render: Fred cuts a 12 inch piece of rope. Then he cuts a second piece of rope that is 3/2 longer than the first piece. Is the second piece shorter or longer than the first piece? Explain. Answered by Penny Nom. 





How many kilometers to a longitudinal degree? 
20140619 

From cherrielyn: Assuming that earth is a sphere of radius 6380 km,
what is the difference in the latitudes of two cities 270 miles apart
positioned on the same meridian?
Thank you in advanced po! :) Answered by Robert Dawson. 





Long division 
20120607 

From Emily: Simplify the expression using long division (9x^241x6)/(x4) Answered by Penny Nom. 





Great circle course 
20120125 

From Hervé: On the earth, the mathematical formula giving the distance
between two points, and the initial course for a boat on the great circle
is well known.
I need to find the inverse formula, ie knowing an initial position on earth,
and the initial course of the boat, and the distance to run on the great circle,
the formula gives the final position (longitude and latitude). Answered by Robert Dawson. 





Explaining the factoring for the difference of cubes 
20080116 

From Bill: A student asked me where did the "difference of cubes" and "sum of cubes" come from. I did not have an answer for her. She is very bright and understands how they work but wanted to know where they derived from. Any help you can offer would be great. Thanks Answered by Stephen La Rocque. 





Great circles 
20071105 

From Lindsay: Does a sphere have only ONE great circle? Explain? Answered by Stephen La Rocque. 





Finding the center of a circle that goes through three given points 
20070916 

From Gary: I am given three points represented by their Latitude and Longitude. How do I determine the Latitude and Longitude of the center of a circle through the three given points?
The lat/lon of the three points are:
A. N 43 degrees 30.251 min. W 96 degrees 45.695 min.
B. N 43 degrees 30.006 min. W 96 degrees 45.082 min.
C. N 43 degrees 30.719 min. W 96 degrees 45.410 min.
Thanks. Answered by Stephen La Rocque. 





Simplifying a quartic rational expression using long division 
20070614 

From Megan: x+2/12x^4+17x^3+0x^2+8x40= Answered by Stephen La Rocque and Penny Nom. 





How many miles are there in 30 furlongs? 
20060722 

From Jennifer: If there are 8 furlongs in a mile, how many miles are there in 30 furlongs? Answered by Steve La Rocque and Paul Betts. 





A long distance call 
20051205 

From A student: The Small World long distance phone company charges 55cents for the first minute of a long distance call and 23cents for each additional minute.
1. How much would a 10 minute longdistance call cost?
2. If a call costs $4.55. how long did the call last?
3. Write an equation for the total cost, C, of an mminute longdistance call. Answered by Penny Nom. 





Cubic furlongs 
20040111 

From A student: 1 mile=8 furlongs, how many cubic furlongs in a cubic mile? Answered by Penny Nom. 





Some algebra 
20020511 

From A student:
/x  2 ^4/x = 8
/ = square root sign ^ = 4th root of x
also, dividing 2x3 3 6x __________ 4 + 2x
the 2x3 is 2x to the third Answered by Penny Nom. 





The repetend in repeating decimals 
20010321 

From Sharon: What is the name for the bar over the repetend in repeating decimals? Also, what is the name of the long division "house"? Answered by Penny Nom. 





The Earth's Arc 
19980206 

From Robert Dyck: How do I find the arc/mile of the earths surface? What is the arc? Answered by Harley Weston. 





La longueur d'une corde 
20030122 

From Un eleve: Existetil une formule permettant de calculer la longueur d'une corde quelquonque d'un cercle connaissant uniquement le rayon de celuici? Si oui quelle estelle? Answered by Claude Tardif. 





La longueur des segments formant un triangle 
19991005 

From Michel Provencher: Connaissant la longueur des segments formant un triangle,comment détermineton chacun de ses angles si:  il S'agit d'un triangle rectangle
Sachant que la somme des angles d'un triangle est de 180 degrés et sachant par conséquant qu'un des angle est de 90 degrés (triangle rectangle) il reste donc, 90 degrés à partager entre les 2 angles restant. Si les 2 segments formant l'angle droit sont de même longueur on obtient un angle de 45 degrés pour les angles restant soit 1/2 angle droit ce qui ne me pose évidement aucun problème. Quel relation, S'il y en a une, y a til entre la longueur de ces 2 segments et les angles restants.  il S'agit d'un triangle quelconque
Answered by Claude Tardif. 

