# 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.

## Related Topics

- How to Find Arc Length and Sector Area
- How to Find Equation of a Circle
- How to Find the Center and the Radius of Circles

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## A 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

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

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