Dual axis charts, also called combo charts, are great when you have two different kinds of information to present in the same chart. For example, you can have a column chart representing sales data and a line chart representing commission amounts displayed together.
The default combo chart doesn’t include a secondary axis to label the values of the second data set. It’s best to turn this on to make the data clear for chart viewers.
Click the Secondary Axis box for the data you want to display on the alternate axis.
You can change the chart type for each series to anything you want. Use the menus in the Chart Type column to select the chart types you want to use.