The ladder he uses makes a 75° angle with the ground. What is the shortest possible length of the ladder if the top of it is 23 feet off the ground? Round to the nearest whole number.

The ladder, ground, and wall form a right triangle, with the ladder as the hypotenuse. Since the ladder makes a 75° angle with the ground, sin(75°) = 23 ÷ ladder length. Thus the ladder length is 23 ÷ sin(75°) ≈ 23.8 feet, which rounds to 24 feet, choice C.

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