Thursday, January 27, 2011

Good Pi

A common approximation of π is 22/7 = 3.142857. Using 3.141593 as the value of π, compute the percent error introduced by using 22/ instead.

Test Guessing

A ten-question test consists of true-or-false questions. What is the probability that a student who guesses at every answer will get them all wrong?

Volume Tolerance

Each side of a cube must measure 1.00 inches ± 1%. What will be the percent tolerance for the volume?

Great Pyramid

The Great Pyramid of Giza was 280 cubits tall when built. Each side of the base was 440 cubits. What was the volume in cubic cubits? Round your answer to two significant digits.

Coin Toss

You flip a fair coin three times in a row. What is the probability that the coin will land heads up at least twice?

Can Label

Belinda needs to design a label for a can. The can is 43/8" tall and 27/8" in diameter. The label requires 1/8" clearance for the rim at the top and bottom of the can. It must wrap around the can with at least 1/4" overlap for glue. To the nearest 1/16", what are the dimensions of the label Belinda must design?

Wednesday, January 26, 2011

Missing Segment

Line AB is parallel to line CD. Find the measure of segment AE using the information provided. Can you also find the length of segment BE?

Triangle Ratios

Line AB is parallel to line CD. The measure of segment AB is twice the measure of segment CD. What is the ratio between the area of ΔABE and ΔCDE?

Tuesday, January 25, 2011

Compare Areas

Line BD is parallel to line AC. What is the relationship of the area of triangle ABD to triangle BCD?
  1. The areas are the same.
  2. The area of ABD is greater than the area of BCD.
  3. The area of ABD is less than the area of BCD.
  4. Impossible to tell from given information.

Wednesday, January 5, 2011

Room Volume

A room is 15' long, 12' wide, and 8' high. What is the volume of the room in cubic feet?

Triangle Troubles

Find the value of y. Find the area of the triangle. Find the value of x. What is the measure of angle B (the top angle)?

Monday, January 3, 2011


For each of the following three-digit numbers, insert one digit anywhere to make a number divisible by 72.
151, 352, 511, 722, 812, 993

Sunday, January 2, 2011

Meet Vi Hart

For anyone who doubts that math can be fun, take a look at this site created by a young woman with a love for the beauty and weirdness of numbers. Here's a recent video she made.