From the top, K of a building 320 m high, the angles of depression of the top, L and bottom, M of another building on the same horizontal ground are 29° and 41° respectively. (i) Illustrate the information in a diagram. (ii) Calculate, correct to the nearest metre, the height of the other building.

Mathematics
From the top, K of a building 320 m high, the angles of depression of the top, L and bottom, M of another building on the same horizontal ground are 29° and 41° respectively. (i) Illustrate the information in a diagram. (ii) Calculate, correct to the nearest metre, the height of the other building.

ScanSolve AI Answer

a) Step 1: Describe the diagram. For part (i), a diagram illustrating the situation would show:

  • A vertical line segment representing the first building (Building A) with height 320320 m. Let its top be KK and its base be AA'.
  • A second vertical line segment representing the other building (Building B) with unknown height HBH_B. Let its top be LL and its base be MM. Building B is parallel to Building A and on the same horizontal ground.
  • A horizontal line segment AMA'M connecting the bases of the buildings. Let the horizontal distance between the buildings be xx.
  • A horizontal line drawn from KK, parallel to AMA'M.
  • The angle of depression from KK to LL (the top of Building B) is the angle between the horizontal line from KK and the line segment KLKL, which is 2929^\circ.
  • The angle of depression from KK to MM (the base of Building B) is the angle between the horizontal line from KK and the line segment KMKM, which is 4141^\circ.

Step 2: Set up trigonometric equations. Let HAH_A be the height of the first building (320320 m) and HBH_B be the height of the other building. Let xx be the horizontal distance between the buildings. From the angle of depression to the base MM of the other building: tan(41)=HAx=320x\tan(41^\circ) = \frac{H_A}{x} = \frac{320}{x} From the angle of depression to the top LL of the other building: The vertical distance from KK to the level of LL is HAHBH_A - H_B. tan(29)=HAHBx=320HBx\tan(29^\circ) = \frac{H_A - H_B}{x} = \frac{320 - H_B}{x}

Step 3: Calculate the horizontal distance xx. Using the first equation: x=320tan(41)x = \frac{320}{\tan(41^\circ)} x3200.86928674x \approx \frac{320}{0.86928674} x368.110 mx \approx 368.110 \text{ m}

Step 4: Calculate the height of the other building, HBH_B. Using the second equation: 320HB=xtan(29)320 - H_B = x \cdot \tan(29^\circ) Substitute the value of xx: 320HB368.110tan(29)320 - H_B \approx 368.110 \cdot \tan(29^\circ) 320HB368.1100.55430905320 - H_B \approx 368.110 \cdot 0.55430905 320HB204.050320 - H_B \approx 204.050 HB320204.050H_B \approx 320 - 204.050 HB115.950 mH_B \approx 115.950 \text{ m} Rounding to the nearest metre: HB116 mH_B \approx 116 \text{ m}

The height of the other building is *116 m*\boxed{\text{*116 m*}}.

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