A pie chart can show collected data in sectors. Each sector can be labelled, or can be colour coded with a key. When drawing a pie chart, a protractor will be used to draw the angles accurately.

A colorful pie chart is shown with a background of a sunset over the ocean. The title of the pie chart is: Utah Cattle, Inventory by Class, January 1998. The pie wedges are different colors, textures ...

and pie charts -- are used every day, his name is barely remembered. And Playfair's story is as colourful as his graphs -- he was an inventor, economist, revolutionary, and even a conman at times.