x + 2x + (x+24) = 84. 4x + 24 = 84 4x = 84 - 24 4x = 60 x = 60/4 = 15. The sides should be 15, 30 and 39 units. ANSWER CHECK. The found side lengths satisfy the triangle inequalities --- hence, such a triangle does exist. ANSWER. The triangle side lengths, obtained from the condition, are 15, 30 and 39 units.