A = 1/2 h (b1 + b2)
A = 201km square
h = 17km
b2 = 16km
what is b1?
My answer paper gives it as 7.65km but I cannot see how you get there
201 = 1/2(17(b1 + 16) multiply by 2
402 = 17(b1+16) expand
402 = 17b1 + 272
130 = 17b1
b1=130/17 = 7.647