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MathematicsClass 84.1 Looking for Information

4.1 Looking for Information | Class 8 Mathematics Notes

By ConceptScroll Team · Published on 17 July 2026 · 5 min read

4.1 Looking for Information – this guide gives you a concise, exam-ready overview of 4.1 Looking for Information from Class 8 Mathematics, written by ConceptScroll editors and reviewed against the latest NCERT textbook.

Representing Data

This section explains how to represent organized data visually to make it easier to understand and interpret. It introduces different graphical methods such as bar graphs, pictographs, and pie charts. The section explains that graphical representation helps in comparing data quickly and identifying trends or patterns. It details the steps to construct a bar graph, including choosing appropriate scales, labeling axes, and drawing bars proportional to frequencies. The section also covers pictographs, where pictures or symbols represent data quantities, explaining the importance of a clear key to indicate the value of each symbol. Pie charts are introduced as a way to represent data as parts of a whole, with each sector’s angle proportional to the frequency or percentage of the category. The section emphasizes accuracy in drawing graphs and the importance of neatness and clarity. It also discusses how to interpret graphs to answer questions about the data. By the end of the section, students are equipped to convert data tables into various graphical forms and extract meaningful information from them.

📊 Diagram: The section includes diagrams of a bar graph showing the number of students in different sports, a pictograph using symbols to represent fruit preferences, and a pie chart illustrating the percentage distribution of favorite subjects.

🧪 Activity: Activity: Students are given a frequency table of favorite ice cream flavors and asked to draw a bar graph and a pictograph to represent the data.

🔗 Connection: This section leads to the next part of the chapter where students learn to interpret data from graphs and answer related questions.

Frequently asked questions

1. A survey was made to find the type of music that a certain group of young people liked in a city. Adjoining pie chart shows the findings of this survey. From this pie chart answer the following: (i) If 20 people liked classical music, how many young people were surveyed? (ii) Which type of music is liked by the maximum number of people? (iii) If a cassette company were to make 1000 CD's, how many of each type would they make?

Solution:

Let the total number of young people surveyed be N.

(i) From the pie chart, classical music sector corresponds to 90°.

Since total angle in pie chart = 360°, the fraction of people liking classical music = 90/360 = 1/4.

Given number of people liking classical music = 20.

So, (1/4) N = 20 => N = 20 4 = 80.

Therefore, total number of young people surveyed = 80.

(ii) From the pie chart, the sector with the largest angle corresponds to pop music (120°).

Hence, pop music is like

2. A group of 360 people were asked to vote for their favourite season from the three seasons rainy, winter and summer. (i) Which season got the most votes? (ii) Find the central angle of each sector. (iii) Draw a pie chart to show this information.

Solution:

Given total people = 360

Votes:

  • Summer = 90
  • Rainy = 120
  • Winter = 150

(i) Season with most votes = Winter (150 votes).

(ii) Central angle for each sector = (Number of votes / Total votes) * 360°

  • Summer: (90/360)*360 = 90°
  • Rainy: (120/360)*360 = 120°
  • Winter: (150/360)*360 = 150°

(iii) To draw the pie chart:

  • Draw a circle.
  • Use a protractor to measure and draw sectors of 90°, 120°, and 150° corresponding to Summer, Rainy, and Winter respectively.
  • Label each sector a
3. Draw a pie chart showing the following information. The table shows the colours preferred by a group of people. Colours: Blue - 18, Green - 9, Red - 6, Yellow - 3, Total - 36

Solution:

Total number of people = 36

Calculate central angle for each colour:

  • Blue: (18/36)*360 = 180°
  • Green: (9/36)*360 = 90°
  • Red: (6/36)*360 = 60°
  • Yellow: (3/36)*360 = 30°

To draw the pie chart:

  • Draw a circle.
  • Use a protractor to mark sectors of 180°, 90°, 60°, and 30° for Blue, Green, Red, and Yellow respectively.
  • Label each sector with the colour name and number of people.
4. The adjoining pie chart gives the marks scored in an examination by a student in Hindi, English, Mathematics, Social Science and Science. If the total marks obtained by the students were 540, answer the following questions. (i) In which subject did the student score 105 marks? (Hint: for 540 marks, the central angle = 360°. So, for 105 marks, what is the central angle?) (ii) How many more marks were obtained by the student in Mathematics than in Hindi? (iii) Examine whether the sum of the marks obtained in Social Science and Mathematics is more than that in Science and Hindi. (Hint: Just study the central angles).

Solution:

Total marks = 540

Central angle for total marks = 360°

(i) Central angle corresponding to 105 marks = (105/540)*360 = 70°

From the pie chart, the sector with 70° corresponds to English.

Therefore, the student scored 105 marks in English.

(ii) Marks in Mathematics correspond to 120°.

Marks in Hindi correspond to 90°.

Marks in Mathematics = (120/360)*540 = 180

Marks in Hindi = (90/360)*540 = 135

Difference = 180 - 135 = 45 marks

(iii) Marks in Social Science = 90° => (90/360)*

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