Finding the Radius Diameter and Circumference of a Circle

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

• 27cm
• 18cm
• 9cm
• 3cm

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

What is the diameter?

• 8
• 16
• 10
• 4

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

A bicycle tire has a diameter of 27 inches. How far does the bike travel along the ground when the wheel rotates once? What is the circumference of this tire?

• 81
• 15.5
• 27
• 13