Download Proving Triangles Congruent

Proving Triangles Congruent
Lesson 4.2
Geometry Honors
Page 122
Objective
Prove two triangles congruent using the SSS,
the SAS, and the ASA Postulates
Proving Triangles Congruent
What is the minimum information required to
prove that two triangles are congruent?
Note
Figures can not be assumed to be congruent
because they look congruent.
It is necessary to use deductive reasoning to
show congruence.
SSS (Side-Side-Side) Postulate
If three sides of one triangle are congruent to
three sides of another triangle, then the
triangles are congruent.
SAS (Side-Angle-Side) Postulate
If two sides and the included angle of one
triangle are congruent to two sides and the
included angle of another triangle, then the
triangles are congruent.
ASA (Angle-Side-Angle) Postulate
If two angles and the included side of one
triangle are congruent to two angles and the
included side of another triangle, then the
triangles are congruent.
Note
There is no such thing as an Angle-Side-Side
Postulate.
If you try to use it, you will look like an angleside-side!
Homework
Page 124 - 127
Problems
1 - 17 odd
18 – 26 even