Problem

an engineer is planning a new water pipe installation. the circular pipe has a diameter of d=20\text{ cm}d=20 cmd, equals, 20, space, c, m.

what is the area aaa of the circular cross section of this pipe?

give your answer in terms of pi.

The area of the circular cross section of the pipe is

Step-by-step explanation:

we know that

The area of the circle (cross section of the pipe) is equal to

we have

----> the radius is half the diameter

substitute

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.