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from the top of a building 60m high ,the angle of depressions of top and bottom of a tower are 30°and60°.find the height of the tower |
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Answer» : EXPLANATION : Given : Height of building (BC) = 60mAngle of DEPRESSION of top (∠ABE) = 30°Angle of depression of bottom (∠ABD) = 60°Solution : Refer to attachment for diagram.We KNOW alternate angles are equal. ∠ABE = ∠BEF = 30°∠ABD = ∠BDC = 60°Now,In △BDC☆☆☆Since, DCFE is a rectangle so, DC = EF = 20√3m In △BEF ☆☆☆Since, DCFE is a rectangleED = FC ☆ED = BC - BF☆ED = (60 - 20) m☆ED = 40 mHeight of TOWER (ED) = 40 m |
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