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56.Two peoples of equal heights are standing opposite each other on either side ofthe road, which is 90mwide. From a point between them on the road, the anglesof elevation of the top of the poles are 60 and 30°, respectively. Find the heightof the poles and the distances of the point from the poles. |
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Answer» Let AB and CD be the two poles of equal height and their heights beH m. BC be the 80 m wide road. P be any point on the road. Let CPbe x m, therefore BP = (80 – x) .Also, ∠APB = 60° and ∠DPC = 30° In right angled triangle DCP,Tan 30° = CD/CP⇒ h/x = 1/√3⇒ h = x/√3 ---------- (1) In right angled triangle ABP,Tan 60° = AB/AP⇒ h/(80 – x) = √3⇒ h = √3(80 – x)⇒ x/√3 = √3(80 – x)⇒ x = 3(80 – x)⇒ x = 240 – 3x⇒ x + 3x = 240⇒ 4x = 240⇒ x = 60Height of the pole, h = x/√3 = 60/√3 = 20√3.Thus, position of the point P is 60 m from C and height of each pole is 20√3 m.please like the solution 👍 ✔️ |
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