- Definition of Demonstrative Geometry
- Fundamental Concepts of Geometry
- Elements in proving a geometrical theorem
- Corollary and Converse of Theorem

- Supplementary Angle Theorem
- Corollary of Supplementary Angle Theorem
- Straight Angle Theorem
- Corollaries of Straight Angle Theorem
- If two lines intersect each other,than vertical angles are congruent
- SAS Theorem
- Corollary of SAS Theorem
- Playfair's Axiom
- Base Angle Theorem
- Corollary of Base Angle Theorem
- Triangle Sum Theorem
- Exterior Angle Theorem
- Alternate Angles Theorem
- If a transversal intersects two parallel lines