Page 1: Introduction to Triangle Congruence Proofs

This page introduces the fundamental concepts of triangle congruence proofs, focusing on the various methods used to prove triangles congruent.

Definition: Triangle congruence refers to the equality of two triangles in all aspects, including their sides and angles.

The page outlines five main ways to prove triangles congruent:

1. SSS (Side-Side-Side)
2. SAS (Side-Angle-Side)
3. ASA (Angle-Side-Angle)
4. AAS (Angle-Angle-Side)
5. HL (Hypotenuse-Leg)

Highlight: The SSS, SAS, ASA, and AAS methods are the most commonly used in triangle congruence proofs.

The guide also introduces reasons for congruent sides and angles, including:

• Given information
• Vertical angles
• Alternate interior angles
• Corresponding angles
• Definition of midpoint
• Definition of angle bisector
• Reflexive property

Vocabulary: CPCTC (Corresponding Parts of Congruent Triangles are Congruent) is introduced as a key concept in triangle congruence proofs.

This comprehensive introduction sets the foundation for understanding and applying triangle congruence theorems in various geometric scenarios.

Page 3: AAS (Angle-Angle-Side) Congruence Theorem

This page focuses on the AAS (Angle-Angle-Side) congruence theorem, providing a comprehensive explanation and examples of its application in triangle congruence proofs.

Definition: The AAS congruence theorem states that if two angles and a non-included side of one triangle are congruent to two angles and a non-included side of another triangle, then the two triangles are congruent.

The page emphasizes the distinction between AAS and ASA, highlighting that in AAS, the given side is not between the two given angles but opposite to one of them.

Two detailed examples are presented to demonstrate the application of the AAS theorem:

1. A proof involving an angle bisector and a given congruent angle
2. A proof using parallel lines, corresponding angles, and a midpoint

Example: In the first proof, YZ bisects ∠WYX, and ∠YWZ ≅ ∠YXZ. The proof shows how to use this information along with the definition of an angle bisector to establish triangle congruence using AAS.

Highlight: The second example introduces the concepts of corresponding angles and midpoints in the context of parallel lines, demonstrating how these properties can be used in conjunction with AAS to prove triangle congruence.

Each example includes a step-by-step breakdown of the proof, listing statements and reasons for each step. This structured approach helps students understand the logical progression of a triangle congruence proof using the AAS theorem.

The page also includes a visual representation of the AAS theorem, clearly showing the relationship between the congruent angles and side in two triangles.