Answer:
The answer is 6.67 feet, approximately.
Explanation:
The image attached shows the context that the problems refered.
Notice that two acute angles from those triangles are congruent, just because their complement are also congruent.


Remember that the tangent function is defined as

Replacing each equiavlence, we have

Then, we solve for

Thereofre, the answer is 6.67 feet, approximately.