Geometry 2.7 Big Idea: Prove Angle Pair Big Idea: Prove Angle PairRelationships.

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Theorem 2.4: Congruent Supplements Theorem If two angles are supplementary to the same angle (or to congruent angles),then they are congruent.

Transcript of Geometry 2.7 Big Idea: Prove Angle Pair Big Idea: Prove Angle PairRelationships.

Geometry 2.7Geometry 2.7 Big Idea: Prove Big Idea: Prove

Angle PairAngle PairRelationshipsRelationships

Theorem 2.3:Theorem 2.3:Right Angles Right Angles Congruence TheoremCongruence Theorem

All right angles are All right angles are congruent.congruent.

Theorem 2.4:Theorem 2.4:Congruent Supplements Congruent Supplements TheoremTheorem

If two angles are If two angles are supplementary to the supplementary to the same angle (or to same angle (or to congruent angles),then congruent angles),then they are congruent.they are congruent.

ExampleExample

If angles 1 and 3 are supplementary and If angles 1 and 3 are supplementary and angles 5 and 3 are supplementary, angles 5 and 3 are supplementary, then angles 1 and 5 are congruent.then angles 1 and 5 are congruent.

Theorem 2.5:Theorem 2.5:Congruent Complements Congruent Complements TheoremTheorem

If two angles are If two angles are complementary to the complementary to the same angle (or to same angle (or to congruent angles),then congruent angles),then they are congruent.they are congruent.

ExampleExample11 2 32 3

If angles 1 and 2 are If angles 1 and 2 are complementary and angles 1 complementary and angles 1 and 3 are complementary, then and 3 are complementary, then angles 2 and 3 are congruent.angles 2 and 3 are congruent.

Theorem 2.6:Theorem 2.6:Vertical Angles Vertical Angles Congruence TheoremCongruence Theorem

Vertical angles are Vertical angles are congruent.congruent.

ExampleExample

4 24 2 1 3 1 3

Postulate 12:Postulate 12:Linear Pair PostulateLinear Pair PostulateIf two angles form a linear If two angles form a linear

pair, then they are pair, then they are supplementary.supplementary.

ExampleExample

Since angles 1 and 2 form a Since angles 1 and 2 form a linear pair, they must be linear pair, they must be supplementary and supplementary and m m 1 + 1 + mm 2 = 180 2 = 180ºº

Proof 1: Right Angles Proof 1: Right Angles Congruence TheoremCongruence Theorem

Given: PQR and UTS are right Given: PQR and UTS are right anglesangles

Prove: PQR UTSProve: PQR UTS

StatementStatement ReasonReason1. 1. 1.1.2. 2. mm PQR = 90 PQR = 90º;º; 2. 2. m m UTS = 90º UTS = 90º3.3.m m PQR = PQR = mm UTS UTS 3. 3. 4.4. 4.4.5.5. 5. 5.

Given: PQR and UTS are right anglesProve: PQR UTS

ExampleExample

If If mm 1 = 112 1 = 112º, find the º, find the measure of angles 2, 3 & 4.measure of angles 2, 3 & 4.