The long side is 15 meters, and the diagonal (hypotenuse) of the triangle is 20 meters. The cost to build is $⁢50 per meter. What is the total cost to build one of the short sides of the pool?

Use the Pythagorean theorem: the short side is √(20² − 15²) = √175 ≈ 13.23 meters. At $50 per meter, it costs 13.23 × $50 ≈ $661.44. Therefore, the cost is $661.44, choice B.

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