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Pie Chart

Class 8th Mathematics West Bengal Board Solution

Lets Do 2
Question 1.

In this year, we have arranged to explain making of various types of science models in the science exhibition of our school. Everyday students of many schools and guardians are coming to see in huge number. Let's list those who have come in to the exhibition today from 10 am to 12 noon on Sunday.

Let,


(B, G, B, M, G, G, M, B, W, B, W, G, W, G, G, M, M, W, B, B, B, W, W, G, G, W, B, M, M, B, G, G, B, W, M, M, W, M, M, G, G, W, M]

Let's make a frequency table by the raw data using tally marks and make a bar-diagram.


Answer:






Lets Work Out 2
Question 1.

Last year in the month of April, there were 23 academics days in Rohit’s school. Rohit has written the number of students who were present in those 23 days.

Those are -

51 43 51 47 43 51 51 47 38 51

47 51 47 51 47 51 51 43 47 43

51 42

Now I make the frequency chart with tally mark and make bar diagram with the help of this chart.


Answer:




Question 2.

I make a bar diagram showing how many students of our class of 40 help in their household work (in hours) during holiday. Let’s see the bar diagram and try to find out the answer of various questions.



i. Let’s write how many students of our class do the domestic work every holiday from the bar diagram and for how long.

ii. Let’s write how many students help in their domestic work for maximum time.

iii. Let’s write how many students help in their domestic work for two hours on every holiday.


Answer:

i From the graph, we can see that, out of 40 students-


8 students worked for 2 hours, 12 students worked for 3 hours, 14 students worked for 14 hours and 6 students worked for 5 hours.


ii. From the graph, we can see that the maximum working hours are 5 hours and there were 6 students who worked for 5 hours.


iii. From the graph, we can see that the number of students help in their domestic work for two hours on every holiday were 8.



Question 3.

Let’s see the pie chart below and find the answers to the questions.

The pie chart of which types of songs the audience likes to listen:



i. Let’s write how many parts of the total circular region is the sector of the audience of Folk song

ii. Let’s write from the pie chart which type of songs has the most number of listeners

iii. Let’s write which type of songs has the least number of listeners.


Answer:

i. It can be easily seen from the pie-chart that the sector of the audience of Folk song=20% of the total circular region.


It is equal to part of the pie chart.


ii. From the pie- chart, the highest sector with most number of listeners is 40%, which is for audience of modern song.


iii. From the pie- chart, the smallest sector with least number of listeners is 10%, which is for audience of classical music.



Question 4.

Let’s see the pie chart below and find the answers to the questions.

The pie-chart of what kind of programmes the audience likes –



i. Let’s write how many parts of the total circular region is the sector of the audience who watch news in the pie chart.

ii. Let’s write what kind of programme gets the most audience.

iii. Let’s write what kind of programme gets the least audience

iv. Let’s write how many parts of the total audience watch the programmes of sports.


Answer:

i. We can see for news; the coverage is 20° and total pie- chart is for 360°



∴ the sector of the audience who watch news in the pie chart is


ii. We can see for entertainment-based sector we have the most area=240°


=


∴ the sector of the audience who watch entertainment-based part in the pie chart=66.66 %


iii. We can see for information-based sector we have the least area=10°



∴ the sector of the audience watch informative programmes the least.


iv. We can see for sports based sector we have the area=90°



∴ the sector of the audience who watch sports-based part is 1/4 th.



Question 5.

I write the percentage of marks which Shuvam has secured in the final examination of class v below : -


Let’s make the pie chart of this information and write the central angle of each sector.


Answer:


Now, the respective angles will be-


For Mathematics-


=108°


For Environment-


=54°


For Physical education-


=72°


For Bengali-


=54°


For English-


=108°



Question 6.

There is a shop of Madhubabu in our locality. I made a list of various types of things which were being sold in his shop on a particular day.


Now I try to make a pie-chart based on the above information


Answer:

Firstly, we’ll covert in percentage.


The total selling price on that day=320+100+160+140


=720


∴ the percentage of common bread sold


=44.45%


Similarly, the percentage of slice bread sold


=13.89%


And, the percentage of cakes sold


=22.22%


And, the percentage of biscuits sold


=19.44%




Question 7.

I have made a list of things of what the students of class VIII of both the sections like to do during their leisure (one student can like only one subject).


Let’s work out from this data what fraction of the total students prefer which subjects.

Let’s find the central angle of each sector and make pie chart accordingly.


Answer:

Firstly, we’ll covert in fraction.


The total selling price on that day=20+25+27+28+20


=120


∴ the fraction of song



⇒ central angle=


=60°


Similarly, the fraction of poem



⇒ central angle=


=75°


And, the fraction of dancing



⇒ central angle=


=81°


And, the fraction of drama



⇒ central angle=


=84°


And, the fraction of Drawing



⇒ central angle=


=60°


Therefore, we can make pie-chart using these central angles.




Question 8.

I have made a model. I made a chart of expenditure of buying materials.


Let’s make a pie chart with this information and write the central angle of the sectors


Answer:

Firstly, we’ll covert in fraction.

The total expenditure on that day=9+12+25+6+8


=60


∴ the fraction of Art Paper



⇒ central angle=


=54°


Similarly, the fraction of sketch Pen



⇒ central angle=


=72°


And, the fraction of Scissor



⇒ central angle=


=150°


And, the fraction of Colored Paper



⇒ central angle=


=36°


And, the fraction of Pitch board



⇒ central angle=


=48°


Therefore, we can make pie-chart using these central angles.




Question 9.

I made a list of the painters based on the perferences of 450 spectators visiting to an art exhibition on one day.


Let’s make a pie chart with this information and write central angle of the sectors.


Answer:

Firstly, we’ll covert in fraction.

The total no. of spectators=150+120+80+100


=450


∴ the fraction of Jamini Roy



⇒ central angle=


=120°


Similarly, the fraction of Nandalal Basu



⇒ central angle=


=96°


And, the fraction of Chintamonikar



⇒ central angle=


=64°


And, the fraction of Ganesh Pain



⇒ central angle=


=80°


Therefore, we can make pie-chart using these central angles.




Question 10.

A chart was made by asking the name of the favourite season to a group of 180 boys.

Let’s find the answer to the questions from the pie chart given below.



i. Let’s write which season is liked by most of the students and how many liked it?

ii. Let’s write which season is liked by the least number of the students.

iii. Let’s write how many students like summer.

iv. Let’s see the pie chart and make two more new questions and try to find answers to them.

(a) Let’s write how many students like spring.

(b) Let’s write how many students don’t like winter.


Answer:

i. We can see for Winter season sector we have the most area=40%



∴ the number of students of the winter season in the pie chart=72


ii. We can see for Rainy season sector we have the most area=10%



∴ the number of students of the rainy season in the pie chart=18


iii. We can see for Summer season sector we have the most area=40%



∴ the number of students of the summer season in the pie chart=36


iv. Two other question can be-


(a) We can see for Summer season sector we have the most area=40%



∴ the number of students of the summer season in the pie chart=54


(b) We can see for Winter season sector we have the most area=40%



∴ the number of students of the winter season in the pie chart=72


∴ the no. of students who don’t like winters=180-72


=102