# Pie Charts (DI)

The “**pie chart”** is also known as a “circle chart”. A pie chart is a type of graph that represents the data in the circular graph. A pie chart is a circular shaped chart, as the name suggested, it is like a pie divided into multiple sectors or slices to represent numerical data. In a pie chart, the length of the arc or central angle is proportional to the quantity that it represents.

**Some importat point related to Pie Charts:**

- A Pie chart uses a circle to represent data.
- Circle is divided into sectors representing different categories.
- Angle of each sector is proportional to value of parameter.
- Sum of angles of all sectors equals 360° which corresponds to total value of parameter.
- Only one parameter can be plotted on one circle. Normally, used to represent segment-wise share or break-up of total quantity.Hence, not suitable for representing all type of data.
- Simple to interpret and visually very appealing.

**Conversion for Pie chart calculations:**

The pie chart formula is given as

**(Given Data/Total value of Data) × 360°**

For example, a sector representing 20% of total quantity would have an angle of $\frac{1}{5}\times {360}^{0}$= ${72}^{0}$

**Example : **

The following pie-charts show the distribution of students of graduate and post-graduate levels in seven different institutes in a town.

Distribution of students at graduate and post-graduate levels in seven institutes:

**Question : **

What is the total number of graduate and post-graduate level students is institute R?

*Solution*:

Required number | = (17% of 27300) + (14% of 24700) |

= 4641 + 3458 | |

= 8099. |

**Question : **

What is the ratio between the number of students studying at post-graduate and graduate levels respectively from institute S?

*Solution*:

Required ratio = | (21% of 24700) | = | (21 x 24700) | = | 19 | . |

(14% of 27300) | 14 x 27300 | 14 |

**Example : **

The circle-graph given here shows the spendings of a country on various sports during a particular year. Study the graph carefully and answer the questions given below it.

**Question: **

What percent of total spending is spent on Tennis?

**Solution: **

Percentage of money spend on Tennis = | 45 | x 100 | % = 12 | 1 | %. | ||

360 | 2 |

**Question : **

How much percent less is spent on Football than that on Cricket?

**Solution: **

Let the total spendings on sports be Rs. *x*. Then,

Amount spent on Cricket = Rs. | 81 | x x |
= Rs. | 9x |
. | ||

360 | 40 |

Amount spent on Football = Rs | 54 | x x |
= Rs. | 3x |
. | ||

360 | 20 |

Difference = Rs. | 9x |
- | 3x |
= Rs | 3x |
. | ||

40 | 20 | 40 |

Required percentage = Rs. | 3x/40 |
x 100 | % = 33 | 1 | %. | ||||

9x/40 |
3 |