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Recap: A Chain of Reasons

Part of the Congruence & Proof section of Coddy's Geometry journey. Lesson 5 of 63.

Challenge

∠ABC is marked as a right angle. Lines PQ and RS cross at E, and ∠PER is marked as a right angle too. Prove that ∠ABC = ∠QES, then press Check.

Try it yourself

$Write the proof$

Write the proof

All lessons in Congruence & Proof

1What a Proof Is

Given and Prove Statements and Reasons Chaining Equal Parts Your First Full ProofRecap: A Chain of Reasons

4SAS

The Included Angle The SAS Rule SAS with a Shared Side Why SSA Fails SAS or SSS?Recap: SAS

7Using CPCTC

Congruent, Then Equal Proving a Bisector Flowchart Proofs Proving a Midpoint Recap: Using CPCTC

10Isosceles Triangle Proofs

Base Angles in a Proof Equal Angles, Equal Sides Proving Isosceles The Perpendicular Bisector Chasing in Isosceles Shapes Recap: Isosceles Proofs

2Congruent Triangles

Same Size, Same Shape Matching Sides Matching Angles What Congruence Gives Recap: Matching Parts

5ASA and AAS

The Side Between The ASA Rule The AAS Rule ASA or AAS?Recap: ASA and AAS

8Proofs with Vertical Angles

Vertical Angles in Proofs The Bowtie Bowtie with ASA Linear Pairs in Proofs Recap: Vertical Angles

11Similarity Proofs

AA Similarity Two Right Triangles SSS Similarity SAS Similarity Similar, Then Find Recap: Similarity