# Graphical representation of relationships

Relationships can also be graphically displayed.

## Coordinate system

By drawing in two vertical lines, one obtains a **coordinate system**.

!

### Remember

Usually, the

The upward axis is the

**Cartesian coordinate system**is used.The upward axis is the

**y-axis**or**ordinate**. The**x-axis**is also called**abscissa**.## Graph of an relationship

For relationships we have different **value pairs**. We can draw these as points and get the **relationship graph**.

!

### Remember

The order of the values of a point $P(x|y)$ is important. Note: always

**first x, then y**.### Example

Weight (in kg) | Price (in €) |
---|---|

1 | 4 |

2 | 8 |

3 | 12 |

The table gives the following points:

$(1|4)$, $(2|8)$ and $(3|12)$

i

### Hint

Watch out for a meaningful scale.