First side + second side + third side = 176 (the perimeter) x + (x+25) + (x-5) = 176 x + (x+25) + (x-5) = 176 ====> 3x + 20 = 176 ====> 3x = 176 - 20 = 156 ====> x == 52 cm. Answer. First side is 52 cm. Second side is 52 + 25 = 77 cm. Third side is 52 - 5 = 47 cm. Check. You need to check that ALL THREE TRIANGLE INEQUALITIES for the side lengths are satisfied. I leave this check to you.