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Matching Angles

Part of the Congruence & Proof section of Coddy's Geometry journey. Lesson 8 of 63.

Matching angles work like matching corners, with one extra step. An angle is named by its vertex, the middle letter: ∠ABC is the angle at B. In △ABC ≅ △DEF, B matches E, so ∠ABC matches ∠DEF and the two are equal.

$Triangles ABC and DEF with matching angles marked with one, two and three arcs$

The order inside a congruence can be shuffled, so check it each time. In △BCA ≅ △EFD the matching is still B to E, C to F and A to D, and the angle at C still matches the angle at F.

Challenge

You are given △HKG ≅ △MNO. Tap the angle of △MNO that matches ∠K, then press Check.

Try it yourself

$Find the right part on the figure$

Find the right part on the figure

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Congruence & Proof

2Congruent Triangles

Same Size, Same Shape Matching SidesMatching AnglesWhat 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