if M is the mid point of PQ it means PM + MQ = PQ 7x + 8 + 5x + 20 = PQ and PM = MQ as the M is the mid point of PQ 7x + 8 = 5x + 20 7x - 5x = 20 - 8 2x = 12 x = 6 it means PQ = 7(6) + 8 + 5(6) + 20 = 42 + 8 + 30 + 20 = 50 + 50 = 100 and PM = MQ = 50