# 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}×{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.

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