# How to Find the Area and Circumference of Circles

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

## Step by step guide to solve Circles

• In a circle, variable $$r$$ is usually used for the radius and $$d$$ for diameter and $$π$$ is about $$3.14$$.
• Area of a circle $$=πr^2$$
• Circumference of a circle $$=2πr$$

### 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 $$=πr^2$$,
$$r=6$$ $$in$$, 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 $$=2πr$$
$$r=9$$ $$cm$$ , then: Circumference $$=2π(6)=12π$$
$$π=3.14$$ then: Circumference $$=12×3.14=37.68$$ $$cm$$

## Exercises for Solving Circles

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

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. $$\color{blue}{Area: \ 379.94 \ cm^2 , \ Circumference: \ 69.08 \ cm}$$

36% OFF

X

## How Does It Work?

### 1. Find eBooks

Locate the eBook you wish to purchase by searching for the test or title.

### 3. Checkout

Complete the quick and easy checkout process.

## Why Buy eBook From Effortlessmath?

Save up to 70% compared to print

Help save the environment