Congruent Polygons

Congruent Figures

Figures that can be mapped onto each other using rigid motions

Rigid Motion (Isometry)

Transformation preserving distance and angle measure

Corresponding Parts

Matching sides and angles in congruent figures

CPCTC

Corresponding Parts of Congruent Triangles are Congruent

Reflexive Property

A figure is congruent to itself

Symmetric Property

If ∆ABC ≅ ∆DEF, then ∆DEF ≅ ∆ABC.

Transitive Property

If ∆ABC ≅ ∆DEF and ∆DEF ≅ ∆JKL, then ∆ABC ≅ ∆JKL.

Congruence Statement

A way to show vertex correspondence

Composition of Rigid Motions

Sequence of transformations (e.g., reflection + translation

Properties of Triangle Congruence

Triangle congruence is reflexive, symmetric, and transitive

Third Angles Theorem

If two angles of one triangle are congruent to angles of another triangle, then the third angles are congruent.

Third Angles Theorem example