The square has length
. Its perimeter, which is the amount of wire used to make the square, must therefore be
.
The remaining amount of wire,
cm (not
), is used to make the circumference of the circle (
).
You now know the radius of the circle and the side length of the square, so you can find the area of both shapes now.
When you find
, notice that the required expression is
, so the hint is that you should leave the expression as is without expanding the term in the square or combining fractions.
^2 )
You can take out the constant in the second term's denominator
^2)
and differentiate using the chain rule, which will give you the required answer.
