- A line parallel to a side
- Whole sides, and the converse
- Why it works, and three lines
- The ratio of the sides
- Finding a side or x
- Why the theorem works
- Three similar triangles
- Legs and the other piece
- Proving a² + b² = c²
- Slope is the same everywhere
- Medial triangles
- Trapezoids and circles
- Unlocks after
- Opens up