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An octagon inscribed in a circle |
2002-01-10 |
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From Kent:
A circle of 30 in. diameter has an octagon (8 equal chords) inscribed in it. What is the length of each chord?
Answered by Chris Fisher. |
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Nickles, dimes, quarters and fifty cent pieces |
2002-01-08 |
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From A parent:
The total for all coins counted is $4,564.50 The last coin added to the pile is a 50 cent piece There are 8 times as many 50 cent pieces as there are quarters There are 6 times as many dimes as nickles How many of each are there?
Answered by Penny Nom. |
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All of the Christmas trees are fifty-five percent off. |
2002-01-08 |
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From A teacher:
All of the Christmas trees are fifty-five percent off. Madison bought a tree and paid $103.50. Assuming no tax, what was the original price of the tree?
Answered by Penny Nom. |
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Ses points de discontinuités est les irrationnelles |
2002-01-08 |
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From Un eleve:
Je voudrait montrer qu'il n'existe pas de fonction de R--->R tels que ses points de discontinuités est les irrationnelles, en utilisant la methode de "baire".
Answered by Claude Tardif. |
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Maple trees and pine trees |
2002-01-06 |
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From A student:
A team of scientists found that in a forest there was four maple trees for every nine pine trees.How many maple were there if they counted 45 more pine than maples?
Answered by Penny Nom. |
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Catenary |
2002-01-02 |
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From Jason:
I am a high school math teacher. I was asked by a friend who is in architectural design for a method for determining the volume of what he called a Catenary. The Catenary curve is modeled by the equation y=a cosh(x/a). I ran into a mess when I tried to compute the volume of the solid formed by revolving that curve around the y-axis. Any help you can provide would be greatly appreciated.
Answered by Harley Weston. |
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Isoperimetric quotients |
2002-01-02 |
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From A student:
I'm stuck on my GCSE Maths coursework, what do isoperimetric quotients measure?
Answered by Penny Nom. |
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2/3 vs 3/4 |
2002-01-02 |
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From Julia:
So, here's my question. Some of the problems they've had to do starts off with two fractions, and they have to tell whether the two fractions are: - The first one is greater than the second one
- The first one is less than the second one, or
- They are equal.
One day my son had the problem of 2/3 vs 3/4. Without drawing out a pie chart, how in the world can a child "eyeball" a problem like this and tell what the correct answer is? I've also tried to teach about making common denominators, but that's going over his head at this point.
Answered by Denis Hanson and Harley Weston. |
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Fractions to decimals and percents |
2001-12-31 |
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From A student:
2/5 , 4/8 , 4/10 , 3/5 , 6/8 , 7/7 (what is the decimal and percent for each)
1/5 , 1/10 , 1/8 , 1/1 (what is the decimal for each)
100 PERCENT, WHAT IS THE DECIMAL?
The ratio of boys to girls in a class is 1:4. What percent of the class are girls?
Answered by Penny Nom. |
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A hyperbola centered at (0,0) |
2001-12-28 |
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From Carla:
- Find the equation of the hyperbola centered at (0,0) with vertices at (0,3) and (0,-3) that is asymptotic to the lines y=+-5x.
- Find the equation of a hyperbola in standard position foci (1,5) and (1,7) and eccentricity 2.
Answered by Peny Nom. |
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Two algebra problems |
2001-12-24 |
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From Cass:
if the graph of a equation is 2x2 - y2 = 8 passes through point (6,k), find the positive value of k. if 5x2 - 2 x = 1, find positive value of x
Answered by Penny Nom. |
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The probability that the area of a triangle is smaller that 1/8 |
2001-12-21 |
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From Hoda:
Given unit square pick two points on adjacent sides of the square , what is the probability that the area of the resulting triangle is smaller that 1/8? I tried to tackle the problem by first sketching a square with the four vertices at (0,0), (1,1), (0,1) and (1,1). The answer seems to be the area under the curve y=0.25/x between 1 and 0, but how can you integrate such a function when ln0 is undefined? any help would be highly appreciated.
Answered by Andrei Volodin. |
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Feeding Jumbo |
2001-12-21 |
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From Lupe:
There are 2 dogs one named major and the other jumbo. major weighs 100 pounds and jumbo 150 pounds. they eat dry dog food which comes in a 40-pound bag that cost $30. Together, major and jumbo eat a whole bag a week. major eats two fifths of the bag while jumbo eats the rest.How much would it cost to feed jumbo in february, which has 28 days?
Answered by Penny Nom. |
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450 students |
2001-12-19 |
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From Jessie:
My teacher told me that the number of ways of lining up the 450 students in our school is larger than the number of atoms in the universe. Is this right? This question came to Good Question, a regular feature on the CBC Morning Edition radio show in Saskatchewan.
Answered by Denis Hanson and Harley Weston. |
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Getting to B in the shortest time |
2001-12-19 |
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From Nancy:
A motorist in a desert 5 mi. from point A, which is the nearest point on a long, straight road, wishes to get to point B on the road. If the car can travel 15 mi/hr on the desert and 39 mi/hr on the road to get to B, in the shortest possible time if...... A.) B is 5 mi. from A B.) B is 10 mi. from A C.) B is 1 mi. from A
Answered by Penny Nom. |
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