How to Find the Area and Circumference of Circles? (+FREE Worksheet!)

Learn how how to find the Area and Circumference of Circles when you have the radius or the diameter of the circle.

How to Find the Area and Circumference of Circles? (+FREE Worksheet!)

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Step-by-step guide to solving Circles

  • In a circle, variable \(r\) is usually used for the radius and \(d\) for the diameter, and \(π\) is about \(3.14\).
  • Area of a circle \(\color{blue}{=πr^2}\)
  • Circumference of a circle \(\color{blue}{=2πr}\)

Circles – Example 1:

Find the area of the circle.

Solution:

Use area formula: Area \(=πr^2\),
\(r=6\) \(in\), then: Area \(=π(6)^2=36π\)

\(π=3.14\), then: Area \(=36×3.14=113.04\) \(in^2\)

Circles – Example 2:

Find the Circumference of the circle.

Solution:

Use Circumference formula: Circumference \(=2πr \)
\(r=9 \) \(cm\) , then: Circumference \(=2π(9)=18π \)
\(π=3.14\), then: Circumference \(=18×3.14=56.52\) \(cm\)

Circles – Example 3:

Find the area of the circle.

Solution:

Use area formula: Area \(=πr^2\),
\(r=4\) \(in\), then: Area \(=π(4)^2=16π\)

\(π=3.14\), then: Area \(=16×3.14=50.24\) \(in^2\)

Circles – Example 4:

Find the Circumference of the circle.

Solution:

Use Circumference formula: Circumference \(=2πr \)
\(r=6 \) \(cm\) , then: Circumference \(=2π(6)=12π \)
\(π=3.14\), then: Circumference \(=12×3.14=37.68\) \(cm\)

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Exercises for Solving Circles

Find the area and circumference of each circle. \((\pi=3.14)\)

Download Circles Worksheet

  1. \(\color{blue}{Area: \ 50.24 \ in^2 , \ Circumference: \ 25.12 \ in}\)
  2. \(\color{blue}{Area: \ 1,017.36 \ cm^2, \ Circumference: \ 113.04 \ cm}\)
  3. \(\color{blue}{Area: \ 78.5 \ m^2, \ Circumference: \ 31.4 \ m}\)
  4. \(\color{blue}{Area: \ 379.94 \ cm^2 , \ Circumference: \ 69.08 \ cm}\)

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