# Pie chart

## Introduction to Pie Chart

A pie chart, also known as a pie graph, is a circular-shaped graph. William Playfair invented it in 1801. It is divided into sectors, which can be percent, degrees, etc. Pie charts have different types, and here's how a pie chart looks:

If total sales last month was 3600 packets, how many packets of vegetarian sausages were sold?

Vegetarian sausages account for\(\frac{1}{4}\)of the total sales, so \(\frac{1}{4}\times 3600 = 900. \)

Therefore, 900 packets of vegetarian sausages were sold last month.How many packets of beef sausages were sold?

There are \(360^\circ\) in a complete turn.

The beef sector has an angle of \(150^\circ,\) so it is \(\frac{150}{360}\) of the circle, implying \[\frac{150}{369}\times 3600 = 1500. \] Therefore, 1500 packets of beef sausages were sold.

## The Proper Definition

A pie chart (or pie graph) is a circular chart divided into sectors, each sector showing the relative size of each value.

The pie chart shows the amount of time each day that Jethro spends on various activities. What is the angle for the sector of the pie chart representing the time he spends playing a sport?

He spends 14% of his time playing a sport. So the angle for the sector of the pie chart representing the time he spends playing a sport is 14% of \(360^\circ,\) which is equal to \(50.4^\circ.\)