2012 · Q18
The angle of elevation of the tip of a tower from a point on the ground is 45 degrees. Moving 21 m directly towards the base of the tower, the angle of elevation changes to 60 degrees. What is the height of the tower, to the nearest meter?
Elementary MathematicsTrigonometry
- A48 m
- B49 m
- C50 m
- D51 m
Explanation
h = d and h = (d-21)*tan60 give h = 21*sqrt(3)/(sqrt(3)-1) = 49.7 m, i.e. 50 m to the nearest meter.