Transcript 3.1 What are congruent figures?

3.1 What are congruent
figures?
Objective:
After studying this lesson you will be able to
understand the concept of congruent figures
and accurately identify the corresponding
parts of figures.
Still unsure about proofs?
Be patient, you may find you gain some
confidence as we work with triangles!
What you learn about congruent triangles
will help you understand the
characteristics of other geometric figures.
So, about congruent figures….
Congruent figures have the same
size and shape.
In general, two geometric figures are congruent if
one of them could be placed one on top of the
other and fit exactly, point for point, side for side
and angle for angle.
Every triangle has 6 parts
3 sides
3 angles
When we say that
ABC
Congruent triangles
parts are congruent
FED we are saying:
all pairs of corresponding
Remember that an arrow symbol
means “implies”
(“If …, then…”). If the arrow is double
, the
statement is reversible.
Name all of the congruent parts
BOW
B
T
W
O
E
I
Definition: Congruent polygons
all pairs of
corresponding parts are congruent.
KET is a reflection of
K
KIT over KT
reflects onto
I
1 2
E
reflects onto
reflects onto
3 4
reflects onto
reflects onto
Postulate
reflects onto
by the reflexive
T
property
Any segment or angle is congruent to
itself (reflexive property)
Summary:
Draw two congruent
figures and name all of the
corresponding parts.
Homework: worksheet