I feed to find the circumference

C ≈ 131.95

Step-by-step explanation:

C=2πr

C = 2π(21)

C = 131.95

131.88 inches

step-by-step explanation:

2πr = circumference

2(21)(3.14)

= 131.88

b. 1.25 hr

step-by-step explanation:

if you have a constant speed of 60 mph, then you have a ratio between 60 mi. to 1 hr. dividing both sides by 60 we get the ratio

1 mi. to

then mult. both sides by 75 we get the ratio

75 mi. to

simplifying we get

75 mi. to

or 1.25 hr.