Question

Can you please help me on problem 4 and 5 of my teacher created problem.

Answer 1

4. Area of a disk of diameter D :
`A= \pi*(D/2)^2\approx3.14*(3.5)^2=38.465`

Assuming that you use the usual convention of rouding 5 to the greater number :

A=38.47

5. Diameter of a circle of radius r :
`A= \pi D=47` hence
`D\approx47/3.14\approx14.97`