ACT Math Circle Circumference and Area

What is the circumference, in inches, of a circle with a radius of 8 inches?

•  $4\pi$  

•  $8\pi$  

•  $12\pi$  

•  $16\pi$  

•  $64\pi$  

A circle has a diameter of 14 inches. What is the circumference of the circle, in inches?

• $7\pi$

• $14\pi$

• $28\pi$

• $49\pi$

• $196\pi$

The perimeter of a circular field is 500 feet. Which of the following is closest to the radius of the field, in feet? (Note:  $\pi\approx3.14$  )

• 10

• 50

• 80

• 160

• 250

Circles A, B, and C have radii with measures of x centimeters, 3x centimeters, and 6x centimeters, respectively. What is the ratio of the radius of Circle B to the diameter of Circle C?

• 1:2

• 1:4

• 1:12

• 2:1

• 4:1

A circle has a diameter of 12 meters. What is the area of the circle, in square meters?

• $6\pi$

• $12\pi$

• $36\pi$

• $24\pi$

• $144\pi$

Richard brought his dog to the park and tied his leash to a flagpole while he had a picnic. The dog could reach 12 feet away from the flagpole in any direction. What is the approximate area of ground, in square feet, that the dog could reach from the flagpole? (Note:  $\pi\approx3.14$  )

• 19

• 38

• 75

• 113

• 452

Find the arc length.  Leave your answer in terms of π.

• 7/4π
• 7/2π
• 1/8π
• 45π

Find the length of the bold arc.Leave pi in your answer.

• 5688π ft
• 15.8π ft
• 150.4π ft
• 54,150 ft

Find the arc length of the bolded arc. Give your answer in terms of π.

• (65/12)π cm

• 17.02 cm

• (845/24)π cm

• 26π cm

Alison is jogging on a circular track that has a radius of 140 feet.  She runs along the track from point R to point N, a distance of 230 feet. Find to the nearest degree, the measure of minor arc RN.

• 47
• 74
• 94
• 123