### Theory:

Let us draw a point in the graph. The point is denoted by $$(a,b)$$ where $$a$$ is the distance along the $$X$$ - axis and $$b$$ is the distance along the $$Y$$ - axis. This pair $$(a,b)$$ is called as the ordered pair. The ordered pair helps us identify the point correctly.

The $$x$$ - coordinate in the ordered pair is called as abscissa and the $$y$$ - coordinate in the ordered pair is called as ordinate.

Here, the ordered pair is $$(a,b)$$ where $$a$$ is the $$x$$ - coordinate or the abscissa and $$b$$ is the $$y$$ - coordinate or the ordinate.
Example:
Let us draw a point in the graph and name it as $$A$$. Here, the ordered pair is $$(2,5)$$.

The $$x$$ - coordinate or the abscissa of the ordered pair is $$2$$ units and the $$y$$ - coordinate or the ordinate is $$5$$ units.
Important!
The ordered pair $$(a,b)$$ and $$(b,a)$$ is not the same.