Practice Circumference in Math
Use these practice problems to test your method after reviewing the concept explanation and worked examples.
Quick Recap
The total distance around the outside of a circle; equal to \pi times the diameter or 2\pi r.
Imagine wrapping a string tightly around a circular jar lid, then straightening the string out. That length is the circumference. No matter the size of the circle, the circumference is always \pi times the diameter—roughly 3.14 laps of the diameter around the edge.
Example 1
easyFind the circumference of a circle with radius 5 cm. Leave your answer in terms of \pi.
Example 2
mediumA circular track has a circumference of 400 m. Find the radius of the track to the nearest metre.
Example 3
easyFind the circumference of a circle with diameter 14 cm. Leave your answer in terms of \pi.
Example 4
mediumA bicycle wheel has diameter 70 cm. How far does it travel in 20 complete rotations? Use \pi = \frac{22}{7}.