Khan/khan-exercises — pull request #24229 by savvy2020 (2012-06-19 05:02:39+00:00)
Title: Congruent angles: Fixes #24216

Fixes #24216
The error happens due to the angle being 90 degrees.

The fix checks for ANGLE=90 and if it is so, sets it 89 or 91.

PS: There may be a better fix, for instance changing the congruency.js so that slopes are checked if they can be calculated. But for this exercise I think just not choosing angle 90 works and also the solution need to change as if the angle is 90 all the other angles are congruent.