Circumference of a Circle Area

What formula is used to find the distance around a circle?

• Area

• Surface area

• Circumference

• Volume

Diameter 13.5 in
Find the circumference of the circle.

• 84.79 in

• 42.39 in

• 21.195 in

• 572.265 in 

A bicycle tire has a diameter of 20 inches. How many inches is one full revolution of the wheel?  

• 31.4 in

• 1256 in

• 125.6 in

• 62.8 in

Other than the formula C=πd what is another formula for circumference of a circle?

• C=2π

• C=2πr

• C=πr²

• C=πd²

If the problem ask you to find the distance around a circle, which formula should you use?

• r = 1/2d

• d = 2r

• C = πd

• A = πr²

Your Geometry teacher rents a fast car for the weekend. Her friend, a Physics teacher, uses a stopwatch to time how long it takes your teacher to make one complete revolution about the track. Is this question circumference or area?

• Circumference

• Area

what is the circumference of this circle ?

• 3.14 cm 

• 37.68 cm

• 24 cm

• 68.4 cm

Radius 4 inches
Find the circumference of the circle. 

• 25.12 in

• 12.56 in

• 50.24 in

• 200.96 in

Ray wants to build a fence around his circular garden outside. The garden has a radius of 6 ft. How many feet of fencing does he need?

• 37.68 ft

• 18.84 ft

• 113.04 ft

• 452.16 ft