Let one side of the rectangle = x ....and the other side = 1.25x
Then the perimeter = 2 [ 1x + 1.25x] = 2 [2.25x] = 4.5x
So the side of the square = [4.5 x ] / 4
And the area of the rectangle = x * 1.25x = 1.25x^2 (1)
And the area of the square = ( [4.5 x ] / 4)^2 = [ 20.25/16] x^2 = [81/64]x^2 (2)
So the ratio of (1) to (2) = 1.25x^2 / [ (81/64)x^2 ] = 1.25 / (81/64) = [5/4] / [ 81/64] =
[5/4] * [ 64/81] = [64/4] * [ 5/81] = [16*5] / 81 = 80/81 as EP found!!!