Shape 

Copyright David & Cynthia Thomas, 2009

Circumference & Area of Circles--Exercises

Part I

Do the challenge problem and directed activities in this section.

Part II

Complete the following exercises

1. The ancient Babylonians computed the area of the circle as the square of the circumference divided by twelve.  Did the Babylonian approach overestimate or underestimate the area of the circle?  Which approach produces a better estimate, the Babylonian or Egyptian method?

2. Complete the following table for circles.  Use 3.14159 as an approximation for p.

Radius	Circumference	Area
5 cm
	24 cm
		90 cm^2

Imagine a sphere with a circumference of 25,000 miles (i.e., approximately that of the Earth).  A metal band exactly fits the sphere at the “equator”.  If the circumference of the band is increased by 1 foot, how much will its diameter increase?  Could you fit a sheet of paper between the larger band and the sphere?  A finger?  A basketball?