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The angular elevation of a tower from a ...

The angular elevation of a tower from a point is 30 . As we more 100 m nearer to the base of the tower, the angle of elevation become `60^(@)` . Find the height of the tower and the distance of the first point fromt he base of the tower .

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To solve the problem step by step, we will use trigonometric relationships in right triangles formed by the tower and the points of observation. ### Step 1: Define the Variables Let: - \( h \) = height of the tower - \( x \) = distance from the first point to the base of the tower ### Step 2: Set Up the First Triangle From the first point (let's call it point A), the angle of elevation to the top of the tower is \( 30^\circ \). We can use the tangent function: \[ \tan(30^\circ) = \frac{h}{x} \] We know that \( \tan(30^\circ) = \frac{1}{\sqrt{3}} \), so: \[ \frac{1}{\sqrt{3}} = \frac{h}{x} \] This gives us our first equation: \[ h = \frac{x}{\sqrt{3}} \quad \text{(Equation 1)} \] ### Step 3: Set Up the Second Triangle After moving 100 meters closer to the tower (to point B), the angle of elevation becomes \( 60^\circ \). The new distance from point B to the base of the tower is \( x - 100 \). Using the tangent function again: \[ \tan(60^\circ) = \frac{h}{x - 100} \] We know that \( \tan(60^\circ) = \sqrt{3} \), so: \[ \sqrt{3} = \frac{h}{x - 100} \] This gives us our second equation: \[ h = \sqrt{3}(x - 100) \quad \text{(Equation 2)} \] ### Step 4: Equate the Two Equations for \( h \) Now we have two expressions for \( h \): 1. \( h = \frac{x}{\sqrt{3}} \) 2. \( h = \sqrt{3}(x - 100) \) Setting them equal to each other: \[ \frac{x}{\sqrt{3}} = \sqrt{3}(x - 100) \] ### Step 5: Solve for \( x \) Cross-multiplying gives: \[ x = 3(x - 100) \] Expanding the right side: \[ x = 3x - 300 \] Rearranging gives: \[ 300 = 3x - x \] \[ 300 = 2x \] \[ x = 150 \text{ meters} \] ### Step 6: Find the Height of the Tower Now substitute \( x = 150 \) back into Equation 1 to find \( h \): \[ h = \frac{150}{\sqrt{3}} = 50\sqrt{3} \text{ meters} \] ### Final Answers - Height of the tower \( h = 50\sqrt{3} \) meters - Distance from the first point to the base of the tower \( x = 150 \) meters
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S CHAND IIT JEE FOUNDATION-SOME APPLICATIONS OF TRIGONOMETRY-Unit Test - 6
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  7. Which of the following is /are the value (s) of the the expression ? ...

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  8. If sin A = (2 m n)/( m^(2) + n^(2)) , What is the value of tan A ?

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  9. If sec^(2) theta + tan^(2) theta = (5)/(3) and 0 le theta le (pi)/(2)...

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  10. Evaluate : (5 sin ^(2) 30^(@) + cos ^(2) 45^(@) + 4 tan ^(2) 60^(@))/(...

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  11. Evaluate : ( 5 cos ^(2) 60^(@) + 4 sec^(2) 30^(@) - tan^(2) 45^(@))/( ...

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  12. The value of sin^(2) 1^(@) + sin^(2) 2^(@) + sin^(2) 3^(@)+ . . . . +...

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  13. If tan 2 A = cot ( A - 60^(@)) , where 2 A is an acute angle then th...

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  14. Evaluate : ( 2 cos 53^(@) cosec 37^(@))/(( cos^(2) 29^(@) + cos^(2) 61...

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  15. Evaluate : sin theta cos theta - (sin theta cos (90^(@) - theta) co...

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  16. Using trigonometric identities 5 cosec ^(2) theta - 5 cot ^(2) theta ...

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  17. The angle of elevation of the top of a tower at a horizontal distanc...

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  18. a person aims at a bird on top of a 5 metre high pole with an elevati...

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  19. Horizontal distance between two pillars of different heights is 60 m...

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  20. The angles of elevation of the top of a tower h metre tall from two di...

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