Khan/khan-exercises — pull request #103000 by petercollingridge (2013-10-31 16:08:19+00:00)
Title: Areas of circles and sectors

Add radians to exercise and also make the fractions *a bit* nicer.

For: https://trello.com/c/gMD2axX1/400-modify-existing-exercises-circles-and-arcs-areas-of-circles-and-sectors