Arectangular pool is 18 meters wide and 24 meters long. if you swim diagonally across the pool, how many meters would you be swimming?

Using the Pythagorean theorem, the diagonal measure is found as
  √((18 m)² +(24 m)²) = √(324 +576) m = √900 m
  = 30 m

You would be swimming 30 meters.

X=y+4 is the answe