Geometry October 17, : Proving Angles Congruent

DO NOW 1.Solve for x. 2. Name the property illustrated in each case. a.b.

Agenda Announcements (2 nd hour only) Do Now Review from Friday

Objective/Big Question How do we use basic angle relationships to prove that two angles are congruent?

REVIEW: Properties REFLEXIVE PROPERTY: Everything is congruent to itself SYMMETRIC PROPERTY: You can “flip” equalities and congruencies TRANSITIVE PROPERTY: If two things are both congruent to a third thing, they’re congruent to each other SUBSTITUTION: If two values are equal, you can swap them out

REVIEW: Properties

Let’s look at angles!

NOTES: Vertical Angles Theorem How can we PROVE this?

NOTES: Vertical Angles Theorem

NOTES: Congruent Supplements

NOTES: Congruent Complements

Exercise: Proof

Practice time!