Download 4-2 = Congruent Triangle Theorems

Congruent Triangles
Remember …
• In congruent triangles,
ALL corresponding sides
and angles are congruent.
In the next few sections we’ll
learn some shortcuts so you
only need to know 3 pairs of
sides or angles
(instead of 6)
to show the
triangles
are
congruent.
SSS Postulate
SSS Postulate
Stands for side—side—side
If all 3 sides of one triangle
are congruent to the
corresponding sides of
another triangle, then the
triangles are congruent.
SSS Postulate
• If the sides are the same,
the angles
will
automatically
be the same
too.
Why?
SAS Postulate
SAS Postulate
Stands for side—angle—side
If 2 sides and the angle
between them in one triangle
are congruent to the
corresponding parts of
another triangle, then the
triangles are congruent.
… So here the triangles
AREN’T congruent.
SAS Postulate
Explain why QPR  TSR.
REMEMBER
• SSS
• SAS