Answer:
84 feet to the nearest foot.
Explanation:
We have a right angled triangle with adjacent side (A) = 100 and you want to find the height of the tower, the opposite side (O).
A = 100 , O = ? so we need the tangent , (from SOH-CAH-TOA).
tan 40 = O/ 100
O = 100 tan 40
= 83.9 feet.