Hexstream
commented
9 years ago If you constructed the DE segment by drawing a parallel to the AC segment, that's not exactly right.
You can verify that your solution is wrong by right-click-dragging one (or several) of the original points of the triangle around.
The point E you really want (according to your partial solution) should be exactly perpendicular to the BC segment, right now it's a bit off.
Goal: Construct the incircle of a triangle. An incircle is a circle fully contained in a triangle that is tangent to all three sides.