25 miles
Step-by-step explanation:
We need an illustration to understand the question.
It gives a right angled triangle. Hence we apply pythagoras' theorem:
Hypotenuse² = opposite² + adjacent²
Hypotenuse = distance between the courthouse and the community swimming pool
opposite = 20 miles
adjacent = 15 miles
Hypotenuse² = 20² + 15²
Hypotenuse² = 400 + 225
Hypotenuse² = 625
Hypotenuse = √625
Hypotenuse = 25
Hence, the distance between the courthouse and the community swimming pool is 25 miles