Two buildings are built 10 m apart.

- The angle of depression from the top of the shorter building (Y) to the foot of the taller building (P) is 53°.
- The angle of elevation from the top of the shorter building to the top of the taller building (X) is 28°.

Calculate the height (XP) of the taller building.



Answer :

Absolutely, let's work through this mathematical problem step-by-step!

We are given:
- The distance between two buildings: 10 meters,
- The angle of depression from the top of the shorter building (Y) to the foot of the taller building (P): 53°,
- The angle of elevation from the top of the shorter building to the top of the taller building (X): 28°.

Let's first summarize the situation:
1. Let [tex]\( h_Y \)[/tex] be the height of the shorter building.
2. Let [tex]\( h_{\text{tall}} \)[/tex] be the height of the taller building.
3. Let [tex]\( h_d \)[/tex] be the height difference between the top of the taller building and the top of the shorter building.

### Step 1: Determine the height of the shorter building (h_Y)

To determine [tex]\( h_Y \)[/tex], we'll use the tangent of the angle of depression:
[tex]\[ \tan(53^\circ) = \frac{h_Y}{\text{distance between buildings}} \][/tex]

Given that the distance between the buildings is 10 meters, we have:
[tex]\[ \tan(53^\circ) = \frac{h_Y}{10} \][/tex]

Solving for [tex]\( h_Y \)[/tex], we get:
[tex]\[ h_Y = 10 \times \tan(53^\circ) \][/tex]

Using a calculator to find [tex]\( \tan(53^\circ) \)[/tex]:
[tex]\[ h_Y = 10 \times 1.327 \][/tex]
[tex]\[ h_Y \approx 13.27 \text{ meters} \][/tex]

### Step 2: Determine the height difference (h_d)

Next, we use the angle of elevation to find the height difference [tex]\( h_d \)[/tex] between the tops of the two buildings:
[tex]\[ \tan(28^\circ) = \frac{h_d}{\text{distance between buildings}} \][/tex]

Given the distance between the buildings is still 10 meters, we have:
[tex]\[ \tan(28^\circ) = \frac{h_d}{10} \][/tex]

Solving for [tex]\( h_d \)[/tex], we get:
[tex]\[ h_d = 10 \times \tan(28^\circ) \][/tex]

Using a calculator to find [tex]\( \tan(28^\circ) \)[/tex]:
[tex]\[ h_d = 10 \times 0.5317 \][/tex]
[tex]\[ h_d \approx 5.317 \text{ meters} \][/tex]

### Step 3: Calculate the height of the taller building (h_{\text{tall}})

Finally, to find the height of the taller building, add the height of the shorter building [tex]\( h_Y \)[/tex] to the height difference [tex]\( h_d \)[/tex]:
[tex]\[ h_{\text{tall}} = h_Y + h_d \][/tex]
[tex]\[ h_{\text{tall}} = 13.27 + 5.317 \][/tex]
[tex]\[ h_{\text{tall}} \approx 18.587 \text{ meters} \][/tex]

Thus, the height of the taller building is approximately 18.587 meters.