A ladder 15 m long just reaches the top of a vertical wall. If the ladder makes an angle of 60° with the wall then the height of the wall is

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In the figure, let AC be the ladder and AB is the wall. Join B and C. We get a right-angled triangle ∆ABC, right angled at B. Given, AC = 15m, BAC = 60°. We use trigonometric ratio cos taking AC as the hypotenuse and AB as the base. In ∆ABC,



or,



So, the correct option is (C).

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