Khan/khan-exercises — pull request #25554 by mwittels (2012-07-06 22:36:19+00:00)
Title: Fill-in-the-blanks proof exercise

http://sandcastle.khanacademy.org/media/castles/mwittels:proofsPart1/exercises/geometry_proofs_1.html

The other proof exercise is renamed geometry proofs 2.