Chapter 7 Class 9 Triangles
Concept wise

If two figures have the same shape & size,

they are congruent

 

For example

1.jpg

 

Here,

  AB & PQ have

  • Same shape - both are lines
  • Same size – both are 5 cm

So, they are congruent.

 

How to check if they are congruent?

What is Congruency? - Part 2

We rotate PQ

& superimpose it an AB

 

Since, PQ comes AB exactly…

They are congruent

 

Some common shapes that are congruent are

What is Congruency? - Part 3

 

Congruency Symbol

If two figures are congruent

What is Congruency? - Part 4

We write

  AB ≅ PQ

 

If two figures are not congruent like

 

We write,

  XY ≇ CD

What is Congruency? - Part 5

 

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.