So Lets prove it :

Consider a line

Consider a line

Take any arbitrary point

So now we can say that length of line is a+b

Now we have to square a+b

that will be

Now we have to square a+b

that will be

lets add all the squares and rectangles

This will be a

^{2 }^{ }

^{ }

Now it is a

^{2}+b^{2}
Here there are two rectangle in the above diagram

As we know that Area of rectangle is Length X Width

So it will be a x b

Now lets add every square and rectangle

a

^{2}+ b

^{2}+ a x b + a x bi.e., a

^{2}+ b

^{2}+ 2ab

## Thus

(a+b)

^{2}=a^{2}+ 2ab+b^{2}