The angle of elevation of the top of a tower at a point on the ground is `30^(@)`. If the height of the tower is tripled, find the angle of elevation of the top of the same point.
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The correct Answer is:
To solve the problem step by step, we will use trigonometric principles related to angles of elevation.
### Step 1: Understand the Problem
We have a tower of height \( H \) and the angle of elevation from a point on the ground to the top of the tower is \( 30^\circ \). We need to find the new angle of elevation when the height of the tower is tripled (i.e., the new height is \( 3H \)).
### Step 2: Set Up the First Triangle
Let’s denote:
- \( A \) as the top of the tower,
- \( B \) as the base of the tower,
- \( C \) as the point on the ground from where the angle of elevation is measured.
From triangle \( ABC \):
- The height of the tower \( AB = H \).
- The distance from point \( C \) to the base of the tower \( BC = D \).
- The angle \( \angle ACB = 30^\circ \).
Using the tangent function:
\[
\tan(30^\circ) = \frac{AB}{BC} = \frac{H}{D}
\]
### Step 3: Calculate \( D \) in Terms of \( H \)
We know that:
\[
\tan(30^\circ) = \frac{1}{\sqrt{3}}
\]
Thus, we can write:
\[
\frac{1}{\sqrt{3}} = \frac{H}{D}
\]
Cross-multiplying gives:
\[
H = \frac{D}{\sqrt{3}}
\]
### Step 4: Set Up the Second Triangle
Now, when the height of the tower is tripled, the new height \( AB' = 3H \). We need to find the new angle of elevation \( \theta \) from point \( C \) to the top of the new tower \( A' \).
In triangle \( A'BC \):
- The height \( A'B = 3H \).
- The distance \( BC = D \) remains the same.
Using the tangent function again:
\[
\tan(\theta) = \frac{A'B}{BC} = \frac{3H}{D}
\]
### Step 5: Substitute \( H \) into the Equation
Substituting \( H \) from our earlier calculation:
\[
\tan(\theta) = \frac{3 \left(\frac{D}{\sqrt{3}}\right)}{D}
\]
This simplifies to:
\[
\tan(\theta) = \frac{3}{\sqrt{3}} = \sqrt{3}
\]
### Step 6: Find \( \theta \)
Now, we need to find the angle \( \theta \) such that:
\[
\tan(\theta) = \sqrt{3}
\]
From trigonometric values, we know:
\[
\theta = 60^\circ
\]
### Final Answer
Thus, the angle of elevation when the height of the tower is tripled is:
\[
\theta = 60^\circ
\]
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