Finding Radius, Diameter and Circumference of Circles

If my radius is 10ft, what is my diameter?

• 20ft

• 5ft

• 31.4ft

• 62.8ft

what is the circumference of this circle ?

• 3.14 cm 

• 37.68 cm

• 24 cm

• 68.4 cm

A circular swimming pool is 21 feet in diameter.
How many feet around is the pool?

• 10.5 ft

• 42 ft

• 65.94 ft

• 131.95 ft

If the diameter of a circle is 10 mm, the circumference is approximately ___

• 314 mm

• 3.14 mm

• 31.4 mm

• 20 mm

• radius = 12

  diameter = 24

• radius = 7

  diameter = 14

• radius =17

  diameter = 34

• radius = 4

  diameter = 8

What formula do you use when trying to find perimeter of a circle?

• Area

• Circumference

• Radius

• Diameter

Using the formula, Circumference of a Circle, find the circumference of the circle.

• 107 sq. in.

• 107 in.

• 53 in.

• 53 sq. in.

• 48 cookies
• 24 cookies
• 8 cookies
• 4 cookies

Find the perimeter of the semicircle.

• 12.86cm

• 20.56cm

• 25.12cm

• 50.24cm

What is the circumference of a circle with a diameter of 9?

• 81pi

• 9pi

• 3pi

• 6pi