Area and Circumference of Circles

A circle has a circumference of 16π cm.  Find the area of the circle.

• 64π cm²

• 256π cm²

• 1024π cm²

• 8π cm²

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

A circular ground has an area of 144π sq ft. Jenny rides the bike around it. How far does she travel to complete a single round? 

• 72π ft

• 12π ft

• 24π ft

• 6π ft

If the circumference of a circle is 28π, what is the radius of the circle?

• 28

• 14

• 56

• 196

A circular swimming pool is 21 feet in diameter.
How many feet around is the pool? Round to the nearest hundredth!

• 32.99 ft

• 42 ft

• 65.97 ft

• 131.95 ft

What is the perimeter of this semi circle?

• 3.6π m

• 7.2π m

• 14.4π

• 12.96π

If the word problem is asking you to find the space inside the circle, which formula should you use?

• r = d/2

• d = 2r

• C = πd

• A = πr²

A circle has a circumference of 9π in. What is the area?

• 81π in²

• 4.5π in²

• 20.25π in²

• 9π in²

The homeowners association wants to enclose the playground in a fence. How much fencing is needed?
Is this question finding the area or the circumference?

• area

• circumference

• neither

What is the area of the yellow?

• 25π m²

• 5π m²

• 6.25π m²

• 1.25π m²