This file is about the math topic - Congruence.

1. Filp Model ...............................................Class IXFFlliipp MMooddeell--CCllaassss IIXX1

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. Ð A @ Ð D
5. Ð B @ Ð E
6. Ð C @ Ð 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

5. SSSSSS
IIff wwee ccaann sshhooww aallll 33 ppaaiirrss ooff ccoorrrr..
ssiiddeess aarree ccoonnggrruueenntt,, tthhee ttrriiaanngglleess
hhaavvee ttoo bbee ccoonnggrruueenntt..
Filp Model ...............................................Class IX 5

6. SSAASS
SShhooww 22 ppaaiirrss ooff ssiiddeess aanndd tthhee
iinncclluuddeedd aanngglleess aarree ccoonnggrruueenntt aanndd
tthhee ttrriiaanngglleess hhaavvee ttoo bbee ccoonnggrruueenntt..
IInncclluuddeedd
aannggllee
NNoonn--iinncclluuddeedd
aanngglleess
Filp Model ...............................................Class IX 6

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

8. RRHHSS (( hhyyppootteennuussee lleegg )) iiss uusseedd
oonnllyy wwiitthh rriigghhtt ttrriiaanngglleess,, BBUUTT,,
nnoott aallll rriigghhtt ttrriiaanngglleess..
RRHHSS AASSAA
Filp Model ...............................................Class IX 8

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

14. NNaammee tthhee PPoossttuullaattee ((IIII)) (when possible)
Reflexive
SSAASS
SSAASS SSAASS
Property
Vertical
Angles
Vertical
Angles
Reflexive
Property SSSSAA
Filp Model ...............................................Class IX 14

15. NNaammee tthhee PPoossttuullaattee ((IIIIII)) (when possible)
Filp Model ...............................................Class IX 15

16. (when NNaammee tthhee PPoossttuullaattee ((IIVV po))ssible)
Filp Model ...............................................Class IX 16