“Imagine a pie chart that shows Visuals at 42 percent, Numbers at 36 percent, Stupid Jokes at 15 percent and Random Complaints at 7 percent. Now let’s convert that to a bar chart.” ...

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.

Playfair, who is said to have invented the pie chart, includes moments such as “Rome founded”, “Mahomet’s Flight”, and “America discovered”. He never mentions slavery. With such a ...