CIRCLES

Parts of a Circle

100

A line segment that goes from one side of the circle to the center.

Radius

200

A line that goes from one side of the circle to the other and passes through the center.

Diameter

300

The distance around the circle.

Circumference 

400

Half of the diameter is the what?

Radius

Area of Circle

100

The diameter of a circle is 20 feet. What is the circle's area?

314ft²

200

The radius of a circle is 4 feet. What is the circle's area?

50.24ft²

300

The round base of a copper tea kettle has a diameter of 14 centimeters. What is the base's area?

153.86cm²

400

A merry-go-round has a circular platform with a radius of 12 meters. What is the platform's area?

113.04m²

Circumference of Circle

100

The radius of a circle is 6 kilometers. What is the circle's circumference?

37.68km

200

Lisa has a circular swimming pool. The pool has a diameter of 26 feet. What is the circumference of the pool in feet?

81.64ft

300

A circular container has an opening with a radius of 4.2 inches. What is the circumference of the opening?

26.37in

400

Hugo attaches his A+ test to the refrigerator with a circular magnet. Out of curiosity, he measures the magnet and calculates that it has a diameter of 4 centimeters. What is the magnet's circumference?

12.56cm

BOTH

100

The lens of a telescope has a diameter of 6 feet. What is the distance around the telescope lense?

18.84 ft

200

The circular mirror hanging on Neil's wall has a radius of 9 centimeters. How much space did that mirror take up?

254.34cm²

300

A family room has a circular rug with a radius of 4 feet. How much space does that rug take up?

50.24ft²

400

Claudia drew a circle on the driveway with chalk. The diameter of that circle was 17 inches. What is the distance around the circle?

53.38in