Practice exercises on circumference, area, diameter and radius.
perimeter area circle and other shapes

Circles Mixed Exercises

area, circumference, diameter and radius

Area and circumference both relate to the radius and diameter of a circle. Once you know one, you can find all of the others --It just takes a little math!

Practice Problems

Problem 1

If a circle's diameter is 10, calculate its circumference and area?

circumference = Π×diameter = 10 Π
radius = ÷2 = 10 ÷ 2 =5
area = Π(radius)² = Π(5)² = 25Π
Problem 2

A circle's area is 16Π. What is its circumference?

A = Π (radius)² = 16Π radius² = 16 radius = 4
circumference = 2Π × radius = 2Π × 4 = 8Π
Problem 3

If a circle has a circumference of 26Π, what is its area

circumference = 2Π(radius) = 26Π 2 × radius = 26 radius = 13 area = Π(radius)² = Π(13)² = 169Π

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