Answer:
141.5 in
Explanation
AB // CD // EF
12 / 15 = 21 / y (By the property of 3 parallel lines and its transversals)
y = (15*21) / 12 = 26.25
CD // EF // GH
21 / y = x / 10 21 / 26.25 = x / 10
x = (21*10) / 26.25
x = 8
perimeter of ABHG = (y-14) +15 + y + 10 + (5x-3) + x + 21 + 12 = 141.5