The height (h)(h) of the building across the street is:
\(h= h_1+ 32\)ft (Eq. 1)
Use the tangent of the angle of elevation (\(θ_e= 50° \)) to find \(h_1\), where the opposite side is\(h_1\) and the adjacent side is x:
\(tanθ_e= \frac{opposite \space side}{adjacent\space side}\)
\(tan50° = \frac{h_1}{x}\)
\(x \space tan50° = h_1\)
\(h_1= x\space tan50° \) (Cross multiply x) (Eq. 2)
Substituting Eq. 2 in Eq. 1:
\(h= h_1+ 32\) ft (Eq. 1)
\(h= x\space tan50° + 30\) ft (Eq. 3)
Now we need to know the length of x, so use the tangent of the angle of depression \((θ_d= 20\degree)\) to look for it. Using the height of the window of 32 ft as the opposite side and x as the adjacent side, solve for x
\(tanθ_d= \frac{opposite \space side}{adjacent\space side}\)
\(tan20\degree= \frac{32}{x}\)
\(x\space tan20\degree= 32\)
\(x= \frac{32}{tan20\degree}\)
x=\(\frac{32}{0.3639702343}\)
x=87.9192774144
The value of x remains unrounded because this is not yet the final answer. Substituting this in Eq. 3, the height of the building is:
\(h= x\space tan50\degree+ 32 ft\)
\(h= 87.9192774144\space tan50\degree+ 32\) ft
=104.77810+32 ft
=136.7781
≈136.8 ft
Thus, the building across the street is 136.8 feet high.