One side of a rectangle is longer than the other side by 1cm. If the area is 30cm, find its perimeter.

1 answer

shorter side --- x
longer side ---- x + 1

x(x+1) = 30
x^2 + x - 30 = 0
(x+6)(x-5) = 0
x = -6 or x = 5, but a side can't be negative, so

x = 5
short side is 5
long side is 6

perimeter = 2(5) + 2(6) = 22