A Presidential Proof of the Pythagorean Theorem
As reported by PBS,
President James Garfield developed his own proof in The Journal
of Education (Volume 3 issue161) in 1876. President Garfield studied math
at Williams College (in Williamstown, MA) and taught in the public school
in Pownal, Vermont, for a year or two after graduating. President Garfield
may have been joking when he stated about his proof that, "we think it something
on which the members of both houses can unite without distinction of the
party." A nice feature of mathematical proofs is that they are not subject
to political opinion.
The preceding excerpt is from http://www.pbs.org/teachersource/mathline/concepts/president/activity2.shtm.
There, you can also see a presentation of President Garfield's proof.