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At a point 20 m away from the foot of a ...

At a point 20 m away from the foot of a tower, the angle of elevation of the top of the tower is `30^@` The height of the tower is

A

`20 sqrt(3) m`

B

`(20)/(sqrt(3))m`

C

`(sqrt(3))/(20m )`

D

None of these

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The correct Answer is:
To find the height of the tower based on the given information, we can use trigonometric relationships. Here’s a step-by-step solution: ### Step 1: Understand the scenario We have a tower, and we are standing 20 meters away from its base. The angle of elevation to the top of the tower is 30 degrees. ### Step 2: Define the variables Let: - \( BC \) = height of the tower (which we need to find) - \( AB \) = distance from the point to the foot of the tower = 20 m - \( \angle A = 30^\circ \) ### Step 3: Use the tangent function From trigonometry, we know that: \[ \tan(\theta) = \frac{\text{opposite}}{\text{adjacent}} \] In our case: \[ \tan(30^\circ) = \frac{BC}{AB} \] Substituting the known values: \[ \tan(30^\circ) = \frac{BC}{20} \] ### Step 4: Calculate \( \tan(30^\circ) \) We know that: \[ \tan(30^\circ) = \frac{1}{\sqrt{3}} \] So we can rewrite our equation: \[ \frac{1}{\sqrt{3}} = \frac{BC}{20} \] ### Step 5: Solve for \( BC \) Now, we can cross-multiply to solve for \( BC \): \[ BC = 20 \cdot \frac{1}{\sqrt{3}} \] This simplifies to: \[ BC = \frac{20}{\sqrt{3}} \text{ meters} \] ### Step 6: Rationalize the denominator (optional) To express this in a more standard form, we can rationalize the denominator: \[ BC = \frac{20 \sqrt{3}}{3} \text{ meters} \] ### Final Answer Thus, the height of the tower is: \[ \frac{20 \sqrt{3}}{3} \text{ meters} \] ---
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ARIHANT SSC-PRACTICE SET -PRACTICE SET-3
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