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The angle of elevation theta of the top ...

The angle of elevation `theta` of the top of vertical tower from a point on the ground is `tantheta` where `tantheta=5/12`. One walking 192 meters towards the tower in the same straight line, the elevation is `alpha` where `tanalpha=3/4`. Find the height of the tower.

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To find the height of the tower based on the given information, we can follow these steps: ### Step 1: Set up the problem Let \( H \) be the height of the tower. From point A (the initial position), the angle of elevation to the top of the tower is \( \theta \) where \( \tan \theta = \frac{5}{12} \). The distance from point A to the base of the tower (point C) is \( AC = x \). ### Step 2: Use the tangent function for the first triangle Using the tangent function for triangle ADC: \[ \tan \theta = \frac{H}{AC} \] Substituting the values: \[ \frac{5}{12} = \frac{H}{x} \] This gives us the equation: \[ H = \frac{5}{12} x \quad \text{(Equation 1)} \] ### Step 3: Move to point B When walking 192 meters towards the tower, the new distance from point B to the tower's base is: \[ BC = x - 192 \] At point B, the angle of elevation is \( \alpha \) where \( \tan \alpha = \frac{3}{4} \). ### Step 4: Use the tangent function for the second triangle Using the tangent function for triangle BDC: \[ \tan \alpha = \frac{H}{BC} \] Substituting the values: \[ \frac{3}{4} = \frac{H}{x - 192} \] This gives us the equation: \[ H = \frac{3}{4} (x - 192) \quad \text{(Equation 2)} \] ### Step 5: Set the two equations for height equal Now we have two expressions for \( H \): 1. \( H = \frac{5}{12} x \) 2. \( H = \frac{3}{4} (x - 192) \) Setting them equal to each other: \[ \frac{5}{12} x = \frac{3}{4} (x - 192) \] ### Step 6: Solve for \( x \) Cross-multiplying to eliminate the fractions: \[ 5 \cdot 4x = 3 \cdot 12(x - 192) \] \[ 20x = 36(x - 192) \] Expanding the right side: \[ 20x = 36x - 6912 \] Rearranging gives: \[ 36x - 20x = 6912 \] \[ 16x = 6912 \] \[ x = \frac{6912}{16} = 432 \] ### Step 7: Substitute \( x \) back to find \( H \) Now substitute \( x \) back into Equation 1 to find \( H \): \[ H = \frac{5}{12} \cdot 432 \] Calculating gives: \[ H = \frac{2160}{12} = 180 \] ### Final Answer The height of the tower is \( H = 180 \) meters. ---
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