Step-by-step explanation:
:)..................
1. BC = 9 tan 45 = 9 ft
AC = 9 tan 60 = 9 sqrt(3) ft
AB = AC - BC = 9sqrt3 - 9 ft ~ 6.59 ft
2. G-Zoo = 200sqrt3 / tan 60 = 200 ft
G-Library = 200sqrt3 / tan 30 = 600 ft
Zoo-Library = G-Library - G-Zoo = 600 - 200 = 400 ft