Calculus question

Question

A piece of wire 9 m long is cut into two pieces. One piece is bent into the shape of a circle of radius r and the other is bent into a square of side s. How should the wire be cut so that the total area enclosed is:

a) a maximum? r= and s=.

b) a minimum? s= and s=.

Answer 1

4s is given to the square

9 - 4s is given to the circle (circumference)

2πr = 9 - 4s

r = (9 - 4s) / 2π

Area = s² + πr²

Area = s² + π[(9 - 4s) / 2π]²

Can you simplify, determine first derivative, set equal to zero and answer?