# Rigid Motions & Congruent Triangles

Videos and lessons to help High School students learn how to use the definition of congruence in terms of rigid motions to show that two triangles are congruent if and only if corresponding pairs of sides and corresponding pairs of angles are congruent.

Common Core: HSG-CO.B.7

When we know that two triangles are congruent, we can make conclusions about the sides and angles of the triangles.

Corresponding Parts of Congruent Triangles are Congruent (CPCTC) Theorem:
If two triangles are congruent then corresponding sides are congruent and corresponding angles are congruent.

CPCTC
Identify the corresponding angles and sides of congruent triangles.

Triangle Congruency
Identify corresponding parts of two triangles.

Side-Angle-Side Congruence by basic rigid motions.

Angle-Side-Angle Congruence by Basic Rigid Motions.

Congruence criteria for triangles SAS.

Base angles of isosceles triangles are equal.

Congruence criteria for triangles ASA and SSS.

Congruence criteria for triangles - AAS and HL.

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