Line graphs are created by plotting points on a chart, then drawing a line to join the points together. They are often used to display data such as rainfall, where the data goes up and down (fluctuates) over a period of time. The line joining the points gives us an idea of up and down changes.

This graph shows the monthly rainfall in two cities. Note that the rainfall is measured in inches. We use millilitres to measure rainfall in Australia.

Monthly rainfall for Portland and Montreal

Look carefully at the picture. What must a line graph have?