Circles Review

Radius

100

The diameter of the circle is 18

What is 9?

200

The diameter of the circle is 16

What is 8?

300

The diameter of the circle is 124

What is 62?

400

Find the radius if the circumference of the circle is 18.84 inches.

(Hint: Work backwards)

What is 3?

500

Find the radius if the circumference of the circle is 25.12

(Hint: Work backwards)

What is 4?

Diameter

100

The radius of the circle is 14

What is 28?

200

The radius of the circle is 19

What is 38?

300

The radius is 45.2, what is the diameter?

What is 90.4?

400

The circumference of the circle is 28.26

(Hint: work backwards)

What is 9?

500

The circumference of the circle is 1,133.54

(Hint: Work backwards)

What is 361?

Circumference

100

The formula to find circumference

What is:

C= Pi x Diameter

or

C= 2 x Pi x Radius

200

The diameter of the circle is 10

What is 31.4?

300

The diameter of the circle is 62.5

What is 196.25?

400

The radius of the circle is 18

What is 113.04?

500

The radius of the circle is 50.25

What is 315.57?

Area of a Circle

100

The radius of a circle is 8

What is 200.96

200

The formula to find the area of a circle

What is:

A= Pi x R²?

300

The radius of the circle is 9

What is 254.34?

400

The diameter of the circle is 144

What is 16,277.76?

500

The diameter of the circle is 280

What is 61,544?