Solve Applied Problems Involving Parabolas
-An experimental model for a suspension bridge is built. In one section, cable runs from the top of one tower down to the roadway, just touching it there, and up again to the top of a second tower. The towers stand 80 inches apart. At a point between the towers and 20 inches along the road from the base of one tower, the cable is 4 inches above the roadway. Find the height of the towers.
A) 16 in.
B) 16.5 in.
C) 15.5 in.
D) 18 in.

Question

Quizplus · Accepted Answer

The parabola is symmetric, so the vertex is at the midpoint of the towers, 40 inches from each tower. Using the point (20, 4) and the vertex form of a parabola, we find the height of the towers to be 16 inches.