What is Congruency?

If two figures have the same shape & size,

they are congruent

For example

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?

We rotate PQ

& superimpose it an AB

Since, PQ comes AB exactly…

They are congruent

Some common shapes that are congruent are

Congruency Symbol

If two figures are congruent

We write

  AB ≅ PQ

If two figures are not congruent like

We write,

  XY ≇ CD