Hey there, Let's say that the first piece is x cm 1st = x 2nd = x + 25% 3rd = x - 25% 100% = 240 cm 1% = 240 / 100 = 2.4cm x + x + 25 + x - 25 = 100 3x + 25 - 25 = 100 3x = 100 - 25 + 25 3x = 100 3x = 240 cm x = 240 / 3 = 80 cm 1st piece = 80 cm 2nd piece = 80 + (25% x 80) = 80 + 20 = 100cm 3rd piece = 80 cm - (25% x 80) = 80 cm - 20 = 60cm