Euclid I.26 part 3
If two triangles have two angles equal to one another, and either the adjoining side or that subtending one of the equal angles is equal, then the remaining sides and angle are also equal.
Week 2 - Perpendicular line
Vodacom Foundation Resource Centres
van Schooten's theorem start point
Graph of the linear function
Incenter, Excenters, and Orthocentric System
Vivek_Circles and Rectangles