Question

An engineer is planning a new water pipe installation. The circular pipe has a diameter of d=20cm.

What is the area A of the circular cross section of this pipe?
Give your answer in terms of pi.
HELP

Answer 1

we know that
the area A of the circular cross section of the pipe is
A=pi*r²
D=20 cm------------- > r=D/2=20/2=10 cm
then
A=pi*10²=100*pi cm²

the answer is A=100*pi cm²