Many thanks to RM Mentock, Eric, yount, Jukka-Pekka Ikaheimonen, George Huber, Andrej Jakobcic, Ken Duisenberg, Peter B Wells, Juha Saukkola, Dave Tuller, Warren Porter, Gregg Middleton, and Jeffrey Harris for sending solutions.

The hypotenuse of the 12 inch isoceles right triangle has a length of sqrt(12^2 + 12^2) = sqrt(288), which is not equal to 17 = sqrt(289).

This could also be an error in rounding.

The problem has been used as a Geometry Forum Problem this year.