Asailboat leaves port and sails 12 kilometers west and then 9 kilometers north. the sailboat is now kilometers from port

Use the Pythagorean Theorem: (leg)^2 + (leg)^2 = (hypotenuse)^2, often written where a and b are the lengths of the legs of a right triangle, and c is the length of the hypotenuse.

In this problem, a = 9 and b = 12.