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2023 AMC 12A Question 15

AMC12 · 2023 AMC 12A

Question 15

Usain is walking for exercise by zigzagging across a $100$-meter by $30$-meter rectangular field, beginning at point $A$ and ending on the segment $\overline{BC}.$ He wants to increase the distance walked by zigzagging as shown in the figure below ($APQRS$). What angle $\theta=\angle PAB$ $=\angle QPC$ $=\angle RQB=\cdots$ will produce a length that is $120$ meters? (Do not assume the zigzag path has exactly four segments as shown; there could be more or fewer.)

Question illustration
  1. $\arccos\tfrac{5}{6}$
  2. $\arccos\tfrac{4}{5}$
  3. $\arccos\tfrac{3}{10}$
  4. $\arcsin\tfrac{4}{5}$
  5. $\arcsin\tfrac{5}{6}$