Semi Circle and Circle Perimeter

The distance around a circular track is 31.4 yards. What Is the radius of the track?

• r=10

• r=5

• r=98.6

Find the circumference of a circle with a radius of 12.5 mm.

• 37.68mm

• 18.84mm

• 78.54mm

• none of the above

Which expression could be used to find the approximate circumference of the quilt piece?

• 2(pi)16

• 2(pi)8

• 2(8)

• 2(4)

Which method could be used to find the radius of the circle formed by the pinwheel as it spins?

• Divide 9 inches by 2

• Divide 9 inches by pi

• multiply 9 inches by pi

• multiply 9 inches by 2

Which best approximates the circumference of the outer ring of this clip?

• 27cm

• 18cm

• 9cm

• 3cm

What is the circumference?

• 48

• 96

• 24

• 18

What is the radius?

• 18

• 72

• 38

• 14

What is the circumference?

• 36

• 18pi

• 108pi

• 36pi

What is the radius?

• 28

• 15

• 26

• 13

What is the diameter?

• 6.5

• 15

• 26

• 78