Answer:
Step-by-step explanation:
Let CD = x
(x + 40)/2 = 31 The midline is 1/2 the sum of the 2 bases. multiply by 2 on both sides.
x + 40 = 31 * 2
x + 40 = 62 Subtract 40 from both sides.
x +40-40 = 62 - 40 Combine
x = 22
Check
(22 + 40)/2
62 / 2
31 = PQ
