Geometry · Triangles & Congruence

CPCTC

HSG-SRT.B.5

Definition

Corresponding Parts of Congruent Triangles are Congruent, used after a congruence proof.

Examples

  • Once two triangles are proven congruent, every corresponding side and angle is congruent.
  • After proving triangle ABC is congruent to triangle DEF, CPCTC lets you conclude angle A is congruent to angle D.

Key rule

CPCTC only applies after congruence has already been proven, such as by SSS, SAS, ASA, AAS, or HL.

Memory hook

Once congruent, every matching part is congruent.