A mouse has made holes in opposite corners of a rectangular kitchen. The width of the kitchen is 8 feet and the distance between the mouse's holes is 17 feet. What is the length of the kitchen?
We have a right triangle with 17 = the hypotenuse and 8 = one leg
The other leg is the length = sqrt [ 17^2 - 8^2] = sqrt [ 289 - 64 ] = sqrt  = 15 (ft)