A surveyor is standing 25 feet from a building and is looking at the top with an angle of elevation of 65 degrees. How tall was the building?

1 Answer
Dec 4, 2016

The height of the building is 53.653.6 feet.

Explanation:

my drawingmy drawing

Please excuse the crude drawing.

Let x=x= the height of the building.

The base of the triangle is labeled 25 ft, and represents the distance from the building to the surveyor.

The surveyor is standing at the lower right vertex of the triangle.

The angle of elevation is represented by the angle labeled 6565 degrees. An angle of elevation is the angle between the observer (the surveyor) and the line of sight to the object being observed (the top of the building).

To find the height of the building xx, use the tangent of the 6565 degree angle. In a right triangle, the tangent of an angle thetaθ is the ratio between the side opposite the angle (xx) and adjacent to the angle (2525).

tantheta=frac{"opposite"}{"adjacent"]tanθ=oppositeadjacent

tan 65=x/25tan65=x25

Multiply both sides by 2525

25* tan 65 = x/25 * 2525tan65=x2525

25* tan 65 = x/cancel25 *cancel25

25 * tan65=xcolor(white)(aaa)Use a calculator

53.6=x

The height of the building is 53.6 feet.