Circumference of a Circle

Analyze and Reflect

1. Describe the ratios C/d you found. Round this number to the nearest hundredths. Where have you seen this number before? What is its name?

2. How is the circumference of a circle related to its diameter? (Hint: How many times greater is the circumference than the diameter?)

3. Write a formula to find the circumference C of any circle using diameter d and piπ