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If a 30 meter ladder is placed against a 15 meter wall such that it just reaches the top of the wall, then the elevation of the ladder with wall is?

Solution

✅ Correct Option: 1

Let θ\theta be the angle of elevation of the ladder from the horizontal ground. The ladder forms the hypotenuse of a right triangle, with length 3030 m, while the height of the wall is 1515 m.

Thus, sin⁡θ=1530=12\sin\theta=\dfrac{15}{30}=\dfrac{1}{2}, giving θ=30∘\theta=30^\circ.

Note: The wording 'with wall' is imprecise. The angle between the ladder and the wall would be 60∘60^\circ, but the standard angle of elevation is measured from the horizontal, giving the official answer 30∘30^\circ.

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