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Heights & Distances (Right Triangle Trigonometry)
The angle of elevation of a ladder leaning against a wall is 60°, and the foot of the ladder is 4.6 m away from the wall. What is the length of the ladder?
Explanation and memory cue
The ladder forms a right triangle with the wall and the ground. The angle of elevation is 60°, and the foot of the ladder is 4.6 m from the wall, which is the adjacent side to the angle. Using the cosine function: cos(60°) = adjacent/hypotenuse = 4.6 / ladder length. Since cos(60°) = 0.5, ladder length = 4.6 / 0.5 = 9.2 m. Therefore, the length of the ladder is 9.2 meters, which corresponds to option D.