1. The document discusses different postulates for proving triangle congruence, including SSS, SAS, ASA, AAS, RHS, and hypothetical cases like SSA and AAA.
2. It warns that there is no actual SSA or AAA postulate to prove congruence and provides examples of non-congruent triangles that satisfy SSA or AAA.
3. The key postulates listed are SSS, SAS, ASA, AAS, and RHS, with RHS only applying to right triangles.
2. TThhee IIddeeaa ooff CCoonnggrruueennccee
Two geometric figures with
exactly the same size and
shape.
B
A C
F
E D
Filp Model ...............................................Class IX 2
3. CCoorrrreessppoonnddiinngg PPaarrttss
Recap: If all six pairs of corresponding
parts (sides and angles) are congruent,
then the triangles are congruent.
B
A C
DABC @ D
DEF
E
D F
1. AB @ DE
2. BC @ EF
3. AC @ DF
4. A @ D
5. B @ E
6. C @ F
Filp Model ...............................................Class IX 3
4. HHooww mmuucchh ddoo yyoouu
nneeeedd ttoo kknnooww.. .. ..
. . . about two triangles
to prove that they
are congruent?
Filp Model ...............................................Class IX 4
7. AASSAA aanndd AAAASS
AASSAA 22 aanngglleess
aanndd tthhee iinncclluuddeedd ssiiddee
AA
SS
AA
AAAASS 22 aanngglleess aanndd
TThhee nnoonn--iinncclluuddeedd ssiiddee
AA AA
SS
Filp Model ...............................................Class IX 7
9. WWaarrnniinngg:: NNoo SSSSAA PPoossttuullaattee
B
There is no such
thing as an SSA
postulate!
A C
E
D
F
NOT CONGRUENT
Filp Model ...............................................Class IX 9
10. WWaarrnniinngg:: NNoo AAAAAA PPoossttuullaattee
B
A C
E
D
F
There is no such
thing as an AAA
postulate!
NOT CONGRUENT
Filp Model ...............................................Class IX 10
11. TThhee CCoonnggrruueennccee PPoossttuullaatteess
SSS correspondence
ASA correspondence
SAS correspondence
AAS correspondence
RHS correspondence
SSA correspondence
AAA correspondence
Filp Model ...............................................Class IX 11
12. NNaammee tthhee PPoossttuullaattee ((II))
(when possible)
SSAASS AASSAA
SSSSAA SSSSSS
Filp Model ...............................................Class IX 12
13. NNaammee tthhee PPoossttuullaattee (when possible)
AASSAA
AAAAAA
SSAASS
SSSSAA
Filp Model ...............................................Class IX 13