Understanding Pie Graph

A pie chart is a picture of data that looks like a circle or pie. The size of the data is shown by the size of the slices of the pie. To show data in the form of a pie chart, you need both a list of numerical variables and a list of categorical variables. In a pie chart, the length of the arc of each slice, as well as the area and central angle it makes, are proportional to the amount it shows.

What is a pie chart?

A pie chart is a type of chart that shows data in the shape of a circle. It is one of the most common graphs used to show information about the real world by using the shapes of circles, spheres, and angles. A pie chart is in the shape of a circle. The whole pie represents the whole set of data, and each slice of the pie represents a separate set of data.

Pie Chart Example

Let’s look at an example of a pie chart that shows how the ingredients for a butter cake are put together.

Example: In this case, the whole pie has a value of 100. It is cut into 10 sections or slices. The different colours represent the things that went into making the cake. What is the exact amount of each of the ingredients that each colour in this pie chart represents?

Solution:- We can see that the pie is cut into 10 pieces or sectors. To figure out how much of each ingredient goes into the cake, we divide the value of the whole sector, which is 100, by the number of sectors. So, 100 ÷ 10 = 10. So, based on how the colours are split up in the pie chart, we can say:

Pie Chart Formula

We know that the value of the pie as a whole is always 100%. A circle also makes an angle of 360°, which is also known. So, when you add up everything, you get 360°. There are two main ways to make pie charts based on these:

• To calculate the percentage of the given data, we use the formula: (Frequency ÷ Total Frequency) × 100

• To convert the data into degrees we use the formula: (Given Data ÷ Total value of Data) × 360°

Using the steps below, we can figure out what a pie chart’s percentage is.

• Sort the given information into groups and figure out the total.

• Separate the different groups

• Turn the numbers into a percentage

• Figure out the degrees

Let us understand the above steps using an example.

Example: Look at the following pie chart, which shows how much money Ana spent at the fair. The amount spent on each category is shown by the colour. The total value of the data is 20, and here’s how to figure out how much was spent on each category:

• Ice cream – 4

• Toffees – 4

• Popcorn – 2

• Rides – 10

To convert this into pie chart percentage, we apply the formula: (Frequency ÷ Total Frequency) × 100

Let’s turn the information above into a percentage:

Amount spent on rides: (10/20)× 100 = 50 %

How much was spent on candies: (4/20) 100 = 20%

How much was spent on popcorn: (2/20) 100 = 10%

How much was spent on ice cream: (4/20) 100 = 20%

Example: Look at the following pie chart, which says that a low-carb diet is best on a given day.

We measure how each slice is cut. We know that the Protein is 180°, the Carb is 108°, and the Fat is 72°.

To find the percentage, we divide each angle by 360 and multiply by 100.

Protein = (180/360) × 100 = 50 %

Carb = (108/360) × 100 = 30 %

Fats = (72/360) × 100 = 20 %

Pie chart data interpretation questions

Pay close attention to the pie chart and answer the following questions:

1) If for a certain number of books, the publisher has to pay Rs. 30,600 for printing, then what will be the amount to be paid for these books?

A. Rs. 19,450

B. Rs. 21,200

C. Rs. 22,950

D. Rs. 26,150

Answer: Option C

Explanation:

Let the amount to be paid for these books be Rs. R

Then, 20 : 15 = 30600

 r = Rs. (30600 x 15/20)= Rs. 22,950.

2)What is the central angle of the part that calculates to the amount of book?

A. 15°

B. 24°

C. 54°

D. 48°

Answer: Option C

Explanation:

Central angle indicating the amount of book= (15% of 360)°

=(15/100x 360)°

= 54°.

Conclusion:

Graphs and charts are good ways to show information because they do it quickly and easily. So, it shouldn’t be a surprise that graphs are often used in print and online media. Sometimes, a graph is a better way to show data than a table because it can show a trend or show how two things compare.