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Related rates and baseball |
2004-04-26 |
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From Bethany:
A baseball diamond is the shape of a square with sides 90 feet long. A player running from second to third base at a speed of 28 feet/ second is 30 feet from second base. At what rate is the player's distance from home plate changing?
Answered by Penny Nom. |
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The problem of Apollonius |
2004-04-25 |
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From Mitja:
There are given 2 circles lying one out of another and one point out of both circles. How to construct a circle passing through a given point and internally tangent to one and externally tangent to the other cirlce?
Answered by Chris Fisher. |
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A Fibonacci triangle |
2004-04-25 |
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From Marcelle:
Is it possible to construct a triangle with sides that are three consecutive Fibonacci numbers?
Answered by Walter Whiteley. |
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Water in a pipe |
2004-04-25 |
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From Marlean:
How much water would be in a 480 foot one inch inside diameter pipe?? In imperial gallons please. thanking you in advance for your help in this matter.
Answered by Penny Nom. |
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Place Value |
2004-04-25 |
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From Santosh:
Q.
Write the Place value of the digits in the following numerals.
1. 5 in 54
2. 3 in 63
Answered by Penny Nom. |
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Marching legion |
2004-04-24 |
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From Art:
A column of soldiers is 100 meters long. Their sargeant at the rear of the column gives the order to march. The sargeant marches alongside the column to its head and then back to the rear, at which point he gives the order to halt. In all, the column of soldiers has marched 100 meters. How far has the sargeant marched? I say 187.5 meters, but those who teach or who have taught mathematics tell me no. Some say much more and some different. What do you say?
Answered by Penny Nom. |
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Three parabolas |
2004-04-24 |
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From A tutor:
I am a maths tutor. One of my year 12 students has given me this assignment. Many parts are ambiguous.
I am trying to determine the equation of the line segment AB. Given that A has an incline of 10 degrees below the horizontal, I am assuming that this parabola (although you can only see part of it) has been rotated 10 degree clockwise. Am I right in assuming this? If so, how do I derive the equation of the parabola as it will then not fit the general form y = ax squared +bx +c of a parabola.
Also, how is one expected to find the x coordinate of D without the equation of this parabola. To find the equation you need the x-coordinate and therefore be able to find another point on the parabola in order to derive the equation using simultaneous equations.
Answered by Penny Nom. |
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Arrays |
2004-04-23 |
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From Jan:
4x7 = 28
How many arrays can this have? How do you
determine the arrays???
Answered by Penny Nom. |
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square root 125 x 16 |
2004-04-23 |
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From Mike:
how do you simplify a square root of "- square root 125 x16" when x is a variable... i don't really get how to do this....
Answered by Penny Nom. |
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The "22" puzzle and the "1089" puzzle |
2004-04-22 |
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From Marcelle:
1. Choose 3 digits from 1-9
2. Make all the 2 digit numbers you can from these (6)
3. Add the 3 original digits and divide them into the sum from step 2.
The answer is always '22'. I just can't understand why. Can you please help.
Another one related to this is it:
1. Choose a three digit number ensuring the first and third digit are differnt by at least two.
2. Make the reverse three digit number and subtract the smaller one from the larger of these.
3. Take this answer and reverse it and add these two 3 digit numbers .
eg:
643 - 346 = 297
297 + 792 = 1089
it doesn't matter what numbers are used, the results are alwasy the same. eg 22 or 1089
Answered by Paul Betts. |
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Why is ounces abbreviated oz? |
2004-04-22 |
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From Someone curious:
Why is ounces abbreviated oz?
Answered by Chris Fisher. |
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What's it called? |
2004-04-22 |
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From Gerry:
I'm a father and a grandfather and have come up with a game for my offspring to play while we're on the road. When we see a license plate, the object is to be the first one to add all the numbers on it, and come up with THE one digit number that sums them up.
For example: ABC-787 = 7+8+7 = 22 = 2+2 = 4
Another example is 2932 = 2+9+3+2 = 16 = 1+6 = 7
Up 'til now, I've called it just plain "Numerology", but I'm sure that there's a math term for what we're doing, and I'd sure appreciate it if you could tell me what it is!
Answered by Chris Fisher and Penny Nom. |
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Surface area of a cylinder |
2004-04-17 |
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From Kathryn:
How do you find the radius of a cylinder when you are given only the surface area and the height of the cylinder?
Answered by Penny Nom. |
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The line through (4,2) and (4,-8) |
2004-04-17 |
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From Kim:
Write an equation for the line.
Given points (4, -8) and (4,2) are on the line.
I believe m=undefined.
How do I solve for b when m is undefined, and then plug in the values for m, b, and y?
Answered by Penny Nom. |
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Some factoring problems |
2004-04-15 |
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From KJ:
Factor these:
x3+125 -----> (x+5)3
8x3-27 -----> (?)
x2+36 -----> (x+6)2
x4-5x2+4 --> (?)
Answered by Penny Nom. |
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