From a distance of 42 feet from the base of a building, the angle of elevation to the top of the building is 67 degrees. estimate the height of the building to the nearest foot.
a. 18 feet
b. 16 feet
c. 39 feet
d. 99 feet

A diagram would surely help here.  But imagine that you stand at spot A and someone finds that your distance from the base of the building is 42 feet.  Call this point B.
 
Imagine a vertical line from that spot, straight up.  Label the top of this line C.

The acute angle at A is 67 degrees.  You want to find the height of the building, which would be the length of the "opposite side of triangle ABC."
The length of the "adjacent side of triangle ABC" would be 42 feet.

We don't know the length of the hypotenuse, altho' we could easilyl calculate it using the Pyth. Them.

We choose the tangent function to solve for the height of the building (which is the length of the opposite side. 

                                                                         height
By definition, tangent (67 degrees) =
                                                                       42 feet

Find tan 67.  Multiply your result by 42 feet.  This product is the height of the building.