# 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

The Absolute Best Book for 4th Grade Students

## 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 $$=12×3.14=37.68$$ $$cm$$

A Perfect Book for Grade 4 Math Word Problems!

## Exercises for Solving Circles

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

1. 2. 3. 4. 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. $$\color{blue}{Area: \ 379.94 \ cm^2 , \ Circumference: \ 69.08 \ cm}$$

The Best Math Books for Elementary Students

### What people say about "How to Find the Area and Circumference of Circles? (+FREE Worksheet!) - Effortless Math: We Help Students Learn to LOVE Mathematics"?

No one replied yet.

X
51% OFF

Limited time only!

Save Over 51%

SAVE $15 It was$29.99 now it is \$14.99