Question 204755
you are correct ___ a square is the rectangle with the largest area for a given perimeter


let L=length and W=width


2L + 2W = 30 ___ L = 15 - W


Area = L * W 


substituting ___ A = (15 - W) * W = 15W - W^2


the max (squared term is negative) of the parabola lies on the axis of symmetry
___ W = -b / 2a = 15 / 2 = 7.5


substituting ___ L = 15 - 7.5 = 7.5