3-1: Congruent Figures

Honors Geometry

Congruent Figures

• Congruent figures have the same size and shape.

• Two triangles are congruent iff all pairs of corresponding parts are congruent.

• Order of vertices matters when listing congruent figures.

Suppose....

• Suppose the two triangles above are congruent in the following order:

A

B

CF

E

D

Mark these congruent:

• So the two triangles are congruent –

A F AB EF B E BC ED

C D AC FD

ABC FED

Included Angles / Sides

• is included by sides and

• Side is included by angles A and C.

A AB AC

AC

A

B

C

Congruent Polygons

• Two polygons are congruent iff all pairs of corresponding parts (sides and angles) are congruent.

a postulate

• Any segment or angle is congruent to itself. (Reflexive Property).

HOMEWORK

• 3-1 problems.

• R & N on 3-2 (including all theorems)