Question about 180° bisection

[leftysrevenge]

I've been trying to understand (through Google research) what prevents true bisection of 180° angle. Technically you can do it in several steps by constructing a perpendicular ray through the midpoint of a line segment. This can be demonstrated using the compass to find the bisection of any leg of a triangle. So I'm curious why this has been determined as unacceptable with the Bisector tool (considering that it's still possible with two other tools). Unless it's been deemed a cheat.

[pkundrat]

I think this is a consequence of the correct solution of the angle bisection level - which doesnt work for straight angles) - the angle bisection tool is an abbreviation for that solution. What could be done is to add another level to solve the angle bisection for straight angles and only add angle bisection then (similarly to what was done in line transformation tool - levels 7+8).