Pie Charts

The pie-chart or a pie graph is a method of representing a given numerical data in the form of sectors of a circle.

The sectors of the circle are constructed in such a way that the area of each sector is proportional to the corresponding value of the component of the data.

From geometry, we know that the area of the sector of a circle is proportional to the central angle.

So, the central angle of each sector must be proportional to the corresponding value of the component.

Since the sum of all the central angles is 360º , we have

Central angle of the component

=  Value of the component  x 360º 

                      Total value


Useful tips:

1. Read the question carefully

The first and the most important step in solving any Data Interpretation question is to read the question carefully. You should read all the data that comes with the graphs or table in the question. Many a times, the data given below the graph turns out to be more important than most of the numbers in the graphs.

2. Analyse the Data Carefully

The next step is to analyse the given graph/data carefully. Do not try to see the questions first and find out the answers accordingly. You will waste your time following that method. Try to understand the graph. Look at the statistics for each pie chart or a pie graph. Look carefully at the labels.

3. Don’t worry about too much data

Try to understand the question. Sometimes, the question contains lots of data that is unrelated and not required for answering the questions. When you look at the question you may get discouraged by the lengthy tables or by the amount of information below the graphs. But, if you were to understand what the data is about and then look at the question, you may find that you only have to use part of the data. Hence, it is important that you do not get disheartened by the size of the data and skip the question without looking closely at it.

4. Skip Questions that need too much Calculation

Some questions ask too much from you. They require lots of calculation in order to be solved. These questions are known as the speed-breakers. Such questions are best left alone, at least in the first round. Once you have finished solving all the easy questions and still have time for the section to end, you should attempt these questions. If you try such questions, you will lose your precious time on them and may not be able to attempt some simple questions that may follow.

5. Avoid Unnecessary Calculations

We have a habit from our school days to solve questions in a step by step method. This is a very good habit for school exams but a really bad habit when it comes to attempting competitive examination and various entrance test. There are many unnecessary calculations that we do which cost us a precious few seconds per question. Sometimes, there are many steps that can be skipped but we still do it as we are trained to solve in a step by step method. Learn to skip those steps.

6. Pay close attention to the units used

Sometimes, the questions may use a different unit for the question and another unit for the data. 

For example, the data given may be about sales volume in Millions. However, the question may ask about sales volume in lakhs. If you do not pay close attention to the unit, you may chose the wrong answer. 

Another question may talk about two roads for example and may give the time in hours in one case and minutes in another. Always convert the units into the ones asked. So, if the question asks how many minutes it will take, convert the data given in hours into minutes. Or if the question asks in hours, convert the data in minutes to hours.

7. Learn to Approximate

You do not need to find the exact answer always. Many a times, the options given are far enough from each other to give you enough room for approximation. So, for example, if you are asked to divide 362678/181234, you can easily approximate that the answer will be somewhere around 2 by looking at the first 2 numbers only. 54/18 is 2. So, instead of dividing it and finding the accurate answer, try to find an approximate answer. This will give you the correct answer more often than not. If however, the options are close, you will still be able to eliminate 1 or 2 options easily.

8. Don’t assume anything

Sometimes there are questions which asks to find out something holistic data for which is not available. Always be alert enough to see whether the data given is enough to answer the question or not and do not go forward with answering the questions based on assumptions.

9. Learn to skim through data

Some graphs have a lot of data associated them and not all of which is required to solve the questions. Skimming through the data and avoiding mess is an important part of the process. So focus on what is required in the question rather than on all the data.