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The height of a tree is 3\sqrt{3} times the length of its shadow. Find the angle of elevation of the sun.

Heights & Distances

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Answer

Let AB be the tree and BC be the shadow of tree.

The height of a tree is times the length of its shadow. Find the angle of elevation of the sun. Heights and Distances, Concise Mathematics Solutions ICSE Class 10.

Let the length of the shadow (BC) of the tree be x meters.

So, the height of the tree (AB) = 3x\sqrt{3}x meters.

If θ is the angle of elevation of the sun, then we have :

In △ABC,

tan θ=PerpendicularBasetan θ=ABBCtan θ=3xxtan θ=3tan θ=tan 60°θ=60°.\Rightarrow \text{tan θ} = \dfrac{\text{Perpendicular}}{\text{Base}} \\[1em] \Rightarrow \text{tan θ} = \dfrac{AB}{BC} \\[1em] \Rightarrow \text{tan θ} = \dfrac{\sqrt{3}x}{x} \\[1em] \Rightarrow \text{tan θ} = \sqrt{3} \\[1em] \Rightarrow \text{tan θ} = \text{tan 60°} \\[1em] \Rightarrow θ = 60°.

Hence, angle of elevation of sun is 60°.

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