Circumference and Area of Circles

What formula is this used for:
πr²

• Circumference 

• Area

• Surface Area

• Volume

Radius 6 cm
What is the diameter? 

• 36 cm

• 12 cm

• 6 cm

• 3 cm 

Diameter 32 inches
What is the radius?

• 16 inches

• 64 inches

• 96 inches
  96 inches

• 16 ft 

A DVD has a diameter of 15 millimeters. Which equation would help you determine the circumference?

• c = 15π

• C = 2π15

• c = 15 ÷ π

• c = 15 π

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

• Area

• Surface area

• Circumference

• Volume

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

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

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

The circumference of a flower garden is 24π yd. What is the area of the flower garden in terms of pi?

• 144π yd²

• 576 π yd²

• 452.16 yd²

• 1,808.64 yd²

Find the area of the circle.

• 9π cm²

• 36π cm²

• 3π cm²

• 2.25π cm²