UsefulLinks
Mathematics
Geometry
1. Foundations of Euclidean Geometry
2. Angles
3. Parallel and Perpendicular Lines
4. Logic and Geometric Proofs
5. Triangles
6. Right Triangles and Trigonometry
7. Similarity
8. Quadrilaterals and Polygons
9. Circles
10. Geometric Transformations
11. Three-Dimensional Geometry
12. Coordinate Geometry
3.
Parallel and Perpendicular Lines
3.1.
Basic Definitions
3.1.1.
Parallel Lines
3.1.1.1.
Definition and Properties
3.1.1.2.
Notation for Parallel Lines
3.1.1.3.
Distance Between Parallel Lines
3.1.2.
Perpendicular Lines
3.1.2.1.
Definition and Properties
3.1.2.2.
Notation for Perpendicular Lines
3.1.2.3.
Right Angles and Perpendicularity
3.1.3.
Skew Lines
3.1.3.1.
Definition and Properties
3.1.3.2.
Distinguishing from Parallel Lines
3.2.
Transversals and Angle Relationships
3.2.1.
Definition of a Transversal
3.2.2.
Identifying Transversals
3.2.3.
Corresponding Angles
3.2.3.1.
Definition and Properties
3.2.3.2.
Corresponding Angles Postulate
3.2.4.
Alternate Interior Angles
3.2.4.1.
Definition and Properties
3.2.4.2.
Alternate Interior Angles Theorem
3.2.5.
Alternate Exterior Angles
3.2.5.1.
Definition and Properties
3.2.5.2.
Alternate Exterior Angles Theorem
3.2.6.
Consecutive Interior Angles
3.2.6.1.
Definition and Properties
3.2.6.2.
Consecutive Interior Angles Theorem
3.2.7.
Consecutive Exterior Angles
3.2.7.1.
Definition and Properties
3.3.
Proving Lines are Parallel
3.3.1.
Converse of Corresponding Angles Postulate
3.3.2.
Converse of Alternate Interior Angles Theorem
3.3.3.
Converse of Alternate Exterior Angles Theorem
3.3.4.
Converse of Consecutive Interior Angles Theorem
3.3.5.
Perpendicular to Same Line Theorem
3.4.
Perpendicular Bisectors
3.4.1.
Definition of Perpendicular Bisector
3.4.2.
Properties of Perpendicular Bisectors
3.4.3.
Constructing Perpendicular Bisectors
3.4.4.
Perpendicular Bisector Theorem
3.5.
Slope and Parallel/Perpendicular Lines
3.5.1.
Slopes of Parallel Lines
3.5.2.
Slopes of Perpendicular Lines
3.5.3.
Using Slope to Prove Parallelism
3.5.4.
Using Slope to Prove Perpendicularity
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4. Logic and Geometric Proofs