Answer:
3.87 miles
Explanation:
The attached figure gives the relative locations of the courthouse, the library and the pool.
The three locations represent a right triangle with the distance between courthouse - pool as the hypotenuse and the distance between courthouse - library as the vertical leg
By the Pythagorean theorem if c is the hypotenuse and a, b the other two legs

a = distance between courthouse and library = 7 miles
c = distance between courthouse and pool = 8 miles
and we have to find b
So plugging in known values
