# Graphing

A graph is a pictorial representation of the relationship between two

or more physical quantities. Graphs are used frequently both to

present fundamental data on the behavior of physical systems and to

monitor the operation of such systems. The basic principle of any

graph is that distances are used to represent the magnitudes of

numbers. The number line is the simplest type of graph. Below is an

example of a number line graph.

All numbers are represented as distances along the line. Positive

numbers are located to the right of zero, and negative numbers are

located to the left of zero.

The coordinate system of a graph is the framework upon which the

graph is drawn. A coordinate system consists of numbered scales that

give the base and the direction for measuring points on the graph. Any

point on a graph can be specified by giving its coordinates.

Coordinates describe the location of the point with respect to the

scales of the coordinate system. There are several different

coordinate systems that all students must learn and understand how to

6) Midpoint