Congruent Triangles

1
Lesson 4-3

• Congruent Triangles

2
Congruent Figures
Congruent figures are two figures that have the
same size and shape.
IF two figures are congruent THEN they have the
same size and shape.
IF two figures have the same size and shape THEN
they are congruent.
Two figures have the same size and shape IFF they
are congruent.
3
Congruent Triangles - CPCTC
CPCTC
Corresponding Parts of Congruent Triangles are
Congruent
Two triangles are congruent IFF their
corresponding parts (angles and sides) are
congruent.


Vertices of the 2 triangles correspond in the
same order as the triangles are named.

A ? P B ? Q C ? R
Corresponding sides and angles of the two
congruent triangles



4
Congruent Triangles
? Z
? A ? ____

? Y
? B ? _____




? X
? C ? ______

Note
? ZYX
?ABC ? ______
?ABC ? ?XYZ
5
Example
When referring to congruent triangles (or
polygons), we must name corresponding vertices in
the same order.
S U N
R A Y
R
?SUN ? ?RAY
Y
A
N
Also ?NUS ? ?YAR
U
Also ?USN ? ?ARY
S
6
Example
If these polygons are congruent, how do you name
them ?
P
O
U
N
M
E
A
S
T
R

• Pentagon MONTA ? Pentagon PERSU
• Pentagon ATNOM ? Pentagon USREP
• Etc.