An Arch of a Bridge Is Semi-Elliptical, with Major Axis

Multiple Choice

An arch of a bridge is semi-elliptical, with major axis horizontal. The base of the arch is 30 feet across, and the highest part of the arch is 10 feet above the horizontal roadway, as shown in the figure. Find the height of the arch 7 feet from the center of the base.

A) 12.1 ft
B) 8.8 ft
C) 17.7 ft
D) 11.0 ft
E) 7.3 ft