In the figure below, a highway rest area (at D) and radar stations (at A and B) lie on a level east-west line, A is 9,000 feet due west of D. An airplane (at C) is shown directly above the rest area, flying due west at a constant speed of 300 feet per secod and at a constant altitude of 12,000 feet. The airplane is located at a straight-line distance of 15,000 feet from the radar station at A and 13,000 feet from the radar station at B.

Let A, C and D lie in the standard (x,y) coordinate plane such that A is at (0,0) and D is at (9,000, 0). Which of the following equations represents the line along which the airplane is flying?

Options

A. `x = 9,000`
B. `x = 15,000`
C. `y = 12,000`
D. `y = 13,000`

Answer

C