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The shadow of a tower of height (1 +sqrt3 ) metre standing on the ground is found to be 2 metre longer when the sun's elevation is 30^(@), then when the sun's elevation was : |
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Answer» `30^(@)` `therefore"In triangle ABC,"` `2+BD=(1+sqrt3)COT 30^(@)` `or 2+BD=(1+sqrt3)sqrt3` `or BD=(sqrt3+3)-2=sqrt3+1` Now, in triangle ABD `tan alpha=(AB)/(BD)=(1+sqrt3)/(sqrt3+1)=1=1 tan 45^(@)` `therefore alpha=45^(@)` |
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