Put a point H on (9, 2). Sketch a triangle out of the three points. Distance between (-2, 2) and (9, 2) is going to be 11. Distance between (9, 2) and (9, 5) is going to be 3. These correspond to the a and b of the Pythagorean Theorem
c^2=a^2+b^2
c=√11^2+3^2=√130
Square root of 130 is 11.4
