Jack swam directly across the pool, diagonally from one corner to another. Which of these is the best estimate of how far he swam?

• A. 15 feet
• B. 25 feet
• C. 35 feet
• D. 45 feet

Answer: (C)

When you swim from one corner of a rectangular pool to the opposite corner, you’re finding the diagonal of the rectangle. The distance along that diagonal is given by the Pythagorean relation diagonal = sqrt(length^2 + width^2).

If the pool is roughly 30 feet long and about 18 feet wide, the diagonal is sqrt(30^2 + 18^2) = sqrt(900 + 324) = sqrt(1224) ≈ 35 feet. That makes 35 feet a clear, reasonable estimate for how far he swam.

Other plausible dimensions give diagonals in the mid-30s or upper-20s to mid-30s range, so 35 feet is the closest rounded estimate to the actual diagonal.