This gives you 3 equations and 3 variables, If we say the longest side is x, the second side is y, and the third side is z, then we can say x/2 = y, x-7=z, and x+y+z=58. We can then solve by substitution. We can subsitute y for x/2 and z for x-7 into the equation x+y+z=58, and so get x + x/2 + x-7 = 58. We then solve for x with 5x/2= 65, 5x = 130, and x = 26. we can then plug x in to the substitution equations, and get 26/2 =y and 26-7 = z, so x = 26, y = 13, and z = 19. As the only measurement is feet use that.
