Answer:
50
Step-by-step explanation:
20% is 1/5 of 100. So you multiply 10 by 5 and you get 50.
x = 39
there is a theorem that states that the midsegment in a trapezoid is equal to the sum of the bases divided by two
so, (36 + 42)/2 = x
36 + 42 = 78
78/2 = 39