Area of a Circle

Area of a Circle

Calculating the area of a circle

Multiple Choice

Quick check: The circumference describes the

• space inside the circle

• distance around the circle (perimeter)

The circumference is the DISTANCE AROUND THE CIRCLE (PERIMETER)

Now, let's talk about area!

Area of a circle is the amount of space inside the circle.

To calculate area of a circle we multiply 3.14 x radius²

That means we multiply the radius x itself first!

Multiple Choice

Remember that squaring a number (little 2) means multiplying it by itself. What is 3²

• 3

• 6

• 9

Multiple Choice

Remember that squaring a number (little 2) means multiplying it by itself. What is 5²

• 5

• 10

• 25

To calculate area of a circle, multiply the radius (short line) by itself. Then, multiply by 3.14

Multiple Choice

Let's try one! Find the area of this circle:

• 25

• 78.5

• 31.4

 $A=\pi r^2$  

• First, square the radius 

• 5 x 5=25

• Then, multiply by 3.14

• 25 x 3.14=

• 78.5

Multiple Choice

find the area of the circle below.

• 100 cm
• 225 cm
• 9 cm
• 28.26 cm

Multiple Choice

Find the area of the circle

• 43.96

• 153.86

• 87.82

• 307.72