Understanding Circle: Area/Circumference

Finding Radius

100

If the diameter is 5 ft what is the radius?

2.5 ft

200

If the diameter is 20 cm what is the radius?

10 cm

300

If the diameter is 30 km the radius is?

15 km 

400

If the diameter is 40 miles what is the radius?

20 miles 

500

If the diameter is 75 mm what is the radius?

37.5 mm

Circumference - In terms of pi

100

Find circumference: When radius = 5

10π

200

Find Circumference when Radius - 10

20π

300

Find Circumference when Diameter = 30

30π

400

Find Circumference when Radius = 50

100π

500

Find Circumference when Diameter = 75

75π

Area - In terms of pi

100

Find Area when Radius = 4

16π

200

Find Area when Diameter = 14

49π

300

Find Area when diameter = 12

36π

400

Find Area when radius = 12

144π

500

Find Area when Diameter = 50

625π

Solve or Find Circumference or Area

100

Find the diameter if the circumference is 37.68. Use 3.14 as pi.

12

200

Find circumference if radius is 10 in. Use 3.14 as pi. Round to the nearest tenth.

62.8 in

300

Find area if radius is 8 in. Use 3.14 as pi. Round to the nearest tenth.

201.0 sq. in.

400

Find the diameter if the circumference is 18.84. Use 3.14 as pi.

6 

500

If the area is 12.56 square centimeters, what is the diameter? Use 3.14 as pi. 

4 cm

Finding Diameter

100

If the radius is 3 ft what is the diameter?

6ft

200

If the radius is 16 meters what is the diameter?

32 meters

300

If the radius is 14 centimeters what is the diameter?

28 cm

400

If the radius is 7 km what is the diameter?

14 km

500

If the radius is 22.5 inches what is the diameter?

45 in