But first a little warm up…
How much do you need to know?
• To prove two triangles
are exactly alike?
(congruent)
• If all 6 parts (3
corresponding sides
and 3 corresponding
angles) are
congruent….that
would do it.
• Any “shortcuts”?
Postulate 19-Side Side Side
(SSS) Congruence Postulate
• If three sides of one
triangle are congruent
to three sides of
another triangle
• Then the two triangles
are congrurent.
• The remaining parts
are congruent.
C
D
G
T
A
O
CAT DOG
Side CADO
Side CTDG
Side ATOG
Postulate 20-Side-Angle-Side
(SAS) Congruence 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.
C
D
G
T
A
O
CAT DOG
Side CADO
Angle AO
Side ATOG
Use the diagram. Name the
included angle between the pair of
sides given.
For each pair of congruent
triangles, name the pairs of
corresponding sides.
Decide whether enough information is given
to prove the triangles are congruent. If there
is enough information, state the congruence
postulate you would use.
Decide whether enough information is given
to prove the triangles are congruent. If there
is enough information, state the congruence
postulate you would use.
Decide whether enough information is given
to prove the triangles are congruent. If there
is enough information, state the congruence
postulate you would use.
Decide whether enough information is given
to prove the triangles are congruent. If there
is enough information, state the congruence
postulate you would use.
Decide whether enough information is given
to prove the triangles are congruent. If there
is enough information, state the congruence
postulate you would use.
Decide whether enough information is given
to prove the triangles are congruent. If there
is enough information, state the congruence
postulate you would use.
Decide whether enough information is given
to prove the triangles are congruent. If there
is enough information, state the congruence
postulate you would use.
Are these triangles congruent?
8
• By what
rule?
• Could you
use the
distance
formula
to verify
your
claim?
6
4
C E
D
2
-10
-5
A
-2
-4
-6
-8
B F
5
10
Assignment 4.3