Math 3 Unit 3 Lesson: 1A, Transversals 1B, Triangle Congruence Know: Special angles created by parallel lines cut by a transversal. Methods of proving triangles are congruent. Be able to: Determine angle congruency and angle measure in a transversal. Prove two triangles are congruent using mathematical methods.

These are Parallel lines “cut” or intersected by a third line, tranversals . Add >> to indicate parallel lines

Supplementary angles A B C D Vertical angles E F G H Corresponding angles Alt. Interior angles Alt. Exterior angles

Congruent Angles (Same size or angle measure) Supplementary Angles Not Congruent Supplementary Angles Vertical Angles Corresponding Angles Alternate Interior Angles Alternate Exterior Angles

Kahoot: Computational Kahoot: Vocabulary for parallel lines and transversals. Kahoot: Computational

i.e. Their relative angles and sides are equal in measure. Triangle Congruency Corresponding Parts of Congruent Triangles are Congruent (CPCTC) i.e. Their relative angles and sides are equal in measure.

Five ways to prove triangles are congruent Side, Side, Side (SSS) Side, Angle, Side (SAS) Angle, Angle, Side (AAS) Angle, Side, Angle (ASA)

The fifth way is only true for right triangles Hypotenuse, Leg (HL) It means we have two right-angled triangles with the same length of hypotenuse and the same length for one of the other two legs.

Kahoot.it: Name the Congruent Triangle Rules (10 easy questions) Kahoot.it:Congruent Triangles (26 medium questions)

Why isn’t SSA or ASS a valid proof for triangle congruency?

Homework