Solve the Problem $115 \mathrm { ft }$ B) $173 \mathrm { ft }$

Multiple Choice

Solve the problem.
-A conservation officer needs to know the width of a river in order to set instruments correctly for a study of pollutants in the river. From point A, the conservation officer walks 100 feet downstream
And sights point B on the opposite bank to determine that ϴ = 30° (see figure) . How wide is the river
(round to the nearest foot) ?

A) $115 \mathrm { ft }$
B) $173 \mathrm { ft }$
C) $50 \mathrm { ft }$
D) $58 \mathrm { ft }$