If the distance from the boat to the lighthouse is 115 meters and the angle of elevation is 42°, which of the following equations will find the height of the light house?

A. tan 42° = y/115
B. tan 42° = 115/y
C. cos 42° = y/115
D. cos 42° = 115/y

A. tan 42° = y/115

Step-by-step explanation:

Let's imagine there is a triangle here. We have the angle (42°) of the triangle and the adjacent side length(115 meters). We are trying to find the height of the lighthouse(opposite side of the triangle). It is tan that uses adjacent and opposite length, not cos. The calculation will be:

tan x= opposite/adjacent

tan 42° = y/115

y= 0.90 * 115

y= 103.5 meter