Question

The angle of elevation to the top of a water tower from point A on the ground is 19.9°. From point B, 50.0 feet closer to the tower, the angle of elevation is 21.8°. What is the height of the tower? Leave your answer in terms of any trigonometric function.

Answer 1

Answer:

Answer in terms of a trigonometric function :

$h = \frac{20tan(19.9)}{0.4-tan(19.9)}$

Answer in figures

$h = 190.5 feet$

Step-by-step explanation:

Consider the sketch attached below to better understand the problem.

Let x be the distance between point B and the base of the water tower.

$tan (19.9)=\frac{h}{50+x} ---------------equation 1$

$tan (21.8)=\frac{h}{x}----------------equation 2$

From equation 2,

$x =\frac{h}{tan21.8}=\frac{h}{0.4}$

substituting the value of x into equation 1, we get

$tan (19.9)=\frac{h}{50+(\frac{h}{0.4} )}$

$tan 19.9=h\times \frac{0.4}{20+h}$

cross multiplying,

$20\times tan(19.9) +htan(19.9)=0.4h$

$20tan(19.9)= h(0.4-tan(19.9))$

$h= \frac{20tan (19.9)}{0.4-tan (19.9)}$

The height of the tower is $h= \frac{20tan (19.9)}{0.4-tan (19.9)}$ in terms of the trig function "Tan"

The equation can simply be evaluated to get the answer in figures since the angles are given in the question