Question 792008
side 1 and 2 = x
side 3 = 2x - 10
p = s * s * s
90 = x + x + (2x -10)
90 = 4x -10
90 + 10 = 4x -10 + 10
100 = 4x
100/4 = 4x/4
25 = x

check:
90 = 25 + 25 + (2(25) -10)
90 = 50 + 40
90 = 90