A ring-shaped region is shown below. Its inner radius is 8 ft, and its outer radius is 12 ft. Find the area of the shaded region. (Use 3.14 for it. Do not round your answer.)

Step-by-step explanation:

In this problem we want to find the area of a ring-shaped region.

The inner radius of the ring is

while the outer radius of the ring is

The area of the ring is equal to the area of the larger circle minus the area of the smaller circle.

The area of the larger circle is:

The area of the smaller circle is instead

Therefore, the area of the ring is:

cheater

step-by-step explanation:

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.