A person is standing exactly [tex]$36 \, \text{ft}$[/tex] from a telephone pole. There is a [tex]30^{\circ}[/tex] angle of elevation from the ground to the top of the pole. What is the height of the pole?

A. [tex]18 \, \text{ft}[/tex]
B. [tex]12 \sqrt{3} \, \text{ft}[/tex]
C. [tex]18 \, \text{ft}[/tex]
D. [tex]18 \sqrt{3} \, \text{ft}[/tex]



Answer :

To find the height of the telephone pole, given a person standing \(36 \, \text{ft}\) from the base of the pole and an angle of elevation of \(30^\circ\) from the ground to the top of the pole, follow these steps:

1. Understand the problem setup:
- You have a right triangle where:
- The horizontal distance from the person to the pole is the adjacent side.
- The height of the pole is the opposite side.
- The angle of elevation is \(30^\circ\).

2. Use the trigonometric relationship:
- For a right triangle, the tangent of an angle is the ratio of the opposite side to the adjacent side:
[tex]\[ \tan(\theta) = \frac{\text{Opposite}}{\text{Adjacent}} \][/tex]
- Here, \(\theta = 30^\circ\), the opposite side is the height of the pole \(h\), and the adjacent side is the distance \(36 \, \text{ft}\).

3. Set up the equation:
[tex]\[ \tan(30^\circ) = \frac{h}{36} \][/tex]

4. Solve for \(h\):
[tex]\[ h = 36 \times \tan(30^\circ) \][/tex]

5. Use the known value of \(\tan(30^\circ)\):
- \(\tan(30^\circ) = \frac{1}{\sqrt{3}}\)

6. Calculate the height:
[tex]\[ h = 36 \times \frac{1}{\sqrt{3}} = 36 \sqrt{3} \times \frac{1}{3} \][/tex]
[tex]\[ h = 12 \sqrt{3} \, \text{ft} \][/tex]

Therefore, the height of the telephone pole is [tex]\(12 \sqrt{3} \, \text{ft}\)[/tex].