Engine failure forced Robbin to pilot her Cessna150 to an emergency landing. TO land, Robbin's plane glided 17,000 ft over a 15,000-fot stretch of deserted highway. From what altitude did the descent begin?
You're looking for a side of a right-angle triangle. Use the Pythagorean Theorem.
a^2 + b^2 = c^2
15,000^2 + b^2 = 17,000^2
225,000,000 + b^2 = 289,000,000
b^2 = 289,000,000 - 225,000,000
b^2 = 64,000,000
b = 8,000 ft