# Important Questions for CBSE Class 8 Maths Chapter 15 – Introduction to Graphs

## Important Questions Class 8 Maths Chapter 15 – Introduction to Graphs

Maths is a fascinating subject which requires proper analytical and logical skills to solve any problem. To be adept in Maths, one must practise solving many problems. It helps one to  enhance their abilities in interpreting problems and develop a good grip on the subject.

Chapter 15 of Class 8 Maths is about ‘Introduction To Graph’.  Following are the important topics that the chapter covers:

• Introduction to Graphs
• A Bar Graph
• A Pie Graph or A Circle Graph
• A Histogram
• A Line Graphs
• Location of a Point
• Coordinates
• Some Applications

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Out-and-out practice in deciphering queries related to the topic is the only way to gain versatility in  Maths. Extramarks is one of the best and most renowned online educational platforms that helps students in their Class 1 to Class 12  to prepare in all possible ways. Extramarks understands the importance of practising problems when we talk about getting a good hold on Maths.

After rigorous research and analysis of past years’ question papers and NCERT textbooks, our highly qualified and well-experienced faculty members have prepared a list of essential questions in our question bank Important Questions Class 8 Maths Chapter 15. This set of important questions and solutions will help students to clear concepts associated with the chapter Introduction to Graphs. Our experts have given step-by-step solutions using the required formulas to solve each question.

Along with the provision of Important Questions Class 8 Maths Chapter 15, Extramarks also gives students access to CBSE revision notes, CBSE sample papers, and CBSE past year question papers. All these solutions strictly adhere to the latest CBSE syllabus making them the most reliable study materials available in the market today.

## Get Access to CBSE Class 8 Maths Important Questions 2022-23 with Chapter-Wise Solutions

You can also find CBSE Class 8 Maths Chapter-by-Chapter Important Questions here:

 CBSE Class 8 Maths Important Questions Sr No. Chapters Chapters Name 1 Chapter 1 Rational Numbers 2 Chapter 2 Linear Equations in One Variable 3 Chapter 3 Understanding Quadrilaterals 4 Chapter 4 Practical Geometry 5 Chapter 5 Data Handling 6 Chapter 6 Squares and Square Roots 7 Chapter 7 Cubes and Cube Roots 8 Chapter 8 Comparing Quantities 9 Chapter 9 Algebraic Expressions and Identities 10 Chapter 10 Visualising Solid Shapes 11 Chapter 11 Mensuration 12 Chapter 12 Exponents and Powers 13 Chapter 13 Direct and Inverse Proportions 14 Chapter 14 Factorisation 15 Chapter 15 Introduction to Graphs 16 Chapter 16 Playing with Numbers

## Introduction to Graphs Class 8 Important Questions with Solutions

Following are a few questions and their solutions included in our Class 8 Maths Chapter 15 Important Questions. Students may register on our website to get full access to our question bank and its solutions.

Question 1: Use the tables below to draw linear graphs:

(a) The number of days a hillside city received snow in different years.

 Years 2003 2004 2005 2006 Days 8 10 5 12

(b) Population (in thousands) of men and women in a village in different years.

 Years 2003 2004 2005 2006 2007 No. of men 12 12.5 13 13.2 13.5 No. of women 11.3 11.9 13 13.6 12.8

Answer 1: (a) Let us take ‘Years’ along the x-axis and ‘Days’ along the y-axis. Hence, using the data provided by the table, the linear graph that we get is:

(b) Let us take Years along the x-axis and No. of Men and ‘No of Women’ along the y-axis. Hence, using the data provided by the table, the linear graph that we get is:

Question 2: Plot the following points on a graph sheet. Verify if they lie in a line:

(a) A(4,0), B(4,2), C(4,6), D(4,2.5).

(b) P(1,1), Q(2,2), R(3,3), S(4,4).

(c) K(2,3), L(5,3), M(5,5), N(2,5).

Answer 1: First we plot all the points in a graph:

(a)

Hence, we find out that points A, B, C and D lie in the same line.

(b)

Hence, we find out that the points P, Q, R and S also lie in the same line.

(c)

Hence, we find out that points K, L, M and N do not lie in the same line.

Question 3: The following line graph shows the yearly sales figure for a manufacturing company:

(a) What were the sales in (i) 2002 (ii) 2006?

(b) What were the sales in (i) 2003 (ii) 2005?

(c) Compute the difference between the sales in 2002 and 2006.

(d) In which year was there the greatest difference between the sales as compared to the previous year?

Answer 3: (a) (i) Sales in 2002 = Rs. 4 crore.

(ii) Sales in 2006 = Rs. 8 crore.

(b) (i) Sales in 2003 = Rs. 7 crore.

(ii)  Sales in 2005 = Rs. 10 crore

(c) Hence, difference between the sales in 2002 and 2006 = Rs. (8 – 4) crore

(d) Difference between sales in 2006 and 2005 = Rs. (10 – 8) crore = Rs. 2 crore.

Difference between sales in 2005 and 2004 = Rs. (10 – 6) crore = Rs. 4 crore.

Difference between sales in 2004 and 2003 = Rs. (7 – 6) crore = Rs. 1 crore.

Difference between sales in 2003 and 2002 = Rs. (7 – 4) crore = Rs. 3 crore.

Therefore, the maximum sale was in the year 2005 compared to that of 2004.

Question 4: Can there be a time-temperature graph as follows? Justify your answer.

Answer 4: We cannot have different temperatures at the same time.

1. This can be a time-temperature graph, since the temperature increases with the increase in time.
2. This can be a time-temperature graph since the temperature decreases with the decrease in time.
3. This cannot be a time-temperature graph since different temperatures at the same time are not possible.
4. This can be a time-temperature graph since the same temperature at different times is possible.

Question 5: Draw a graph for the following:

(i)

 Side of square (in cm) 2 3 3.5 5 6 Perimeter (in cm) 8 12 14 20 24

Is it a linear graph?

(ii)

 Side of square ( in cm) 2 3 4 5 6 Area ( in cm²) 4 9 16 25 36

Is it a linear graph?

Answer 5: (i) First we plot the graph by taking Side of Square along x-axis and Perimeter along y-axis

Therefore, It is a linear graph.

(ii) First, we plot the graph by taking the Side of the Square along the x-axis and the Area along the y-axis.

Question 6:

The cost of a notebook is Rs.10. Draw a graph after making a table showing the cost of 2,3, 4 …Notebooks. Use it to find

(a) The cost of 7 notebooks

(b) The number of notebooks purchased with Rs 50.

Answer 6: Plotting the graph, we get

(a) Now following the graph we can find that

Cost of 7 notebooks = Rs. 70

(b) Now following the graph we can find that,

No. of notebooks purchased with Rs. 50 = 5

Question 7: Explain the situations represented by the following distance-time graphs.

Answer 7: (a) The graph represents that the object has travelled an equal distance in an equal intervals of time, i.e., the object moves with uniform velocity.

(b) The graph represents that the object moves with uniform velocity for some time and then becomes constant.

(c ) The distance covered by the object reduces gradually, i.e., the body moves with decreasing velocity.

Question 8:

Draw a graph for the radius and circumference of the circle using a suitable scale.

From graph

(a) Find the circumference of the circle when the radius is 42 units.

(b) At what radius will the circumference of the circle be 220 units?

Answer 8: Since we know that,

Circumference of a circle = 2πr = 2 × 22/7 × r = 44r/7

Let us take the radius = 7 units

Therefore, the circumference = 2 × π × r = 44 × 7/7 = 44 units.

Now let us take the radius = 14 units

Therefore, the circumference = 2 × π × r = 44 × 14/7 = 88 units

After we calculate so on, we get the following table. And the graph is plotted as shown below:

 Radius of the circle 7 14 21 28 35 42 Circumference of the circle 44 88 132 176 220 264

Hence, from the graph we find that

(a) The circumference of the circle on taking the radius as 42 units is 264 units.

(b) The circle’s radius will be 35 units taking the circumference as 220 units.

Question 9: Plot the given points on a graph sheet and check if the points lie in a straight line. If not, name the shape they form when joined in the given order.

(a) (1, 2), (2,4), (3,6), (4,8).

(b) (1,1), (1,2), (2,1), (2,2).

(c) (4,2), (2,4), (3,3), (5,4).

Answer 9:  (a) First, we plot the points on the graph as shown below:

Hence, from the graph we find that the points are on a straight line.

(b) First, we plot the points on the graph as shown below:

Hence, from the graph, we find that the points are not in a straight line. The points are in the form of a square.

(c ) First, we plot the points on the graph as shown below:

Hence, from the graph, we find that the points are not in a straight line. The points are forming a triangle.

### Benefits of solving Class 8 maths Chapter 15 Extra Questions

Practice is the prerequisite for being adept in Maths. It helps the student to develop a firm conception of the subject. Practising the Important Questions Class 8 Maths Chapter 15 provided by Extramarks, students are well prepared and proficient to solve any complex problem during examinations.

Following are some benefits of solving the introduction to graphs class 8 important questions:

1. Introduction to Graphs Class 8 Extra Questions is a compilation of some well-picked questions by our experts.  Our qualified academicians have prepared these questions after considering and analysing all the past years’ papers and CBSE textbooks.
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At Extramarks, we understand the importance of solving important questions and we take our role seriously to provide the best resource to the students and help them excel in life. To speed up their learning and improve their academic performance, students must register themselves now, to begin their preparation without any further delay. The learning website of Extramarks provides study materials other than  Important Questions Class 8 Maths Chapter 15 as well, like:

Q.1 Draw the line passing through (2, 3) and (3, 2). Find the coordinates of the points at which this line meets the x-axis and y-axis.

Marks:2
Ans

(2, 3) and (3, 2) meets the x-axis at (5, 0) and y-axis at (0, 5) .

Q.2

Plot the following points. Verify if they lie on a line.
(1, 3), (2, 3), (3, 3), (4, 3)

Marks:2
Ans

Yes, they all lie on a line.

Q.3

Draw a graph for the following.

 Distance in metres 5 10 15 20 25 30 Time in seconds 1 2 3 4 5 6

Is it a linear graph?

Marks:2
Ans

Yes, it is a linear graph.

Q.4

In which year was there the greatest difference between the sales as compared to its previous year?

Marks:3
Ans

In year 2004, sales is 6 million
In year 2005, sales is 12 million

Difference is 6 million. It’s the greatest difference between the sales as compared to its previous year.

Q.5

Find the coordinates of the points A, B, C, D, E and F from the graph.

Marks:2
Ans

A (-4, 0), B (-2, 3), C (1, 3), D (3, 1), E (1, -1), F(-2, -1)