Congruent Triangles
Chapter 4, Section 3
Corresponding Parts of
Congruent Triangles
• Congruent triangles have the same
shape
_____________
and ______________.
size
• “Corresponding parts” of triangles refers to
sides that match in length
the _______________________________
angles that match in degree measure
and ______________________________.
Corresponding Parts of
Congruent Triangles
Y
B
A
C
X
Z
These are congruent triangles. When
writing a congruence statement, you must
________________________________!!
Match up the corresponding parts
ABC  XYZ
_________________---ORDER
MATTERS!!
Definition of Congruent Triangles
• Triangles whose corresponding parts are congruent.
• CPCTC: Corresponding Parts of Congruent
Triangles are Congruent
• Example #1: The two triangles are congruent.
K
– Name all the congruent angles: R
_______  _______
M
_______  _______
_______  _______
S
– Name all the congruent sides: D
_______  _______
_______  _______
W
_______  _______
Congruence Transformations—
rotating, flipping, or moving a shape
• In the picture, ABC  XYZ. Even if you
turn, flip, or slide, XYZ does not
change its size or shape. Therefore, no
matter how you move the triangles, they
are still _____________________.
congruent
X
A
B
C
Z
Y
Example 1:
• Given that GHI  FDE list all of the
congruent corresponding parts.
Example 2:
• Give that YXZ  DXG, find the value of all the
variables.
Y
8x+1
9y+1
Z
X
62o
D
6y+7
G
Example 3:
• The vertices of  RST are R(-3, 0), S(-1, 5),
and T(1, -1), and the vertices of  MNP are
at M(3, 0), N(-1, -1), and P(1, -5).
Is RST  MNP ?
RS=_______
ST=_______
RT=_______
MN=_______
NP=_______
MP=_______