#### Chapters

Chapter 2: Linear Equations in One Variable

Chapter 3: Understanding Quadrilaterals

Chapter 4: Practical Geometry

Chapter 5: Data Handling

Chapter 6: Squares and Square Roots

Chapter 7: Cubes and Cube Roots

Chapter 8: Comparing Quantities

Chapter 9: Algebraic Expressions and Identities

Chapter 10: Visualising Solid Shapes

Chapter 11: Mensuration

Chapter 12: Exponents and Powers

Chapter 13: Direct and Inverse Proportions

Chapter 14: Factorisation

Chapter 15: Introduction to Graphs

Chapter 16: Playing with Numbers

#### NCERT Mathematics Class 8

## Chapter 15: Introduction to Graphs

#### Chapter 15: Introduction to Graphs Exercise 15.10 solutions [Pages 236 - 239]

The following graph shows the temperature of a patient in a hospital, recorded every hour.

1) What was the patient’s temperature at 1 p.m.?

2) When was the patient’s temperature 38.5°C?

3) The patient’s temperature was the same two times during the period given. What were these two times?

4) What was the temperature at 1.30 p.m.? How did you arrive at your answer?

5) During which periods did the patients’ temperature showed an upward trend?

The following line graph shows the yearly sales figures for a manufacturing company.

1) What were the sales in (a) 2002 (b) 2006?

2) What were the sales in (a) 2003 (b) 2005?

3) Compute the difference between the sales in 2002 and 2006.

4) In which year was there the greatest difference between the sales as compared

to its previous year?

For an experiment in Botany, two different plants, plant A and plant B were grown under similar laboratory conditions. Their heights were measured at the end of each week for 3 weeks. The results are shown by the following graph.

1) How high was Plant A after (a) 2 weeks (b) 3weeks?

2) How high was Plant B after (a) 2 weeks (b) 3weeks?

3) How much did Plant A grow during the 3^{rd} week?

4) How much did Plant B grow from the end of the 2^{nd} week to the end of the 3^{rd} week?

5) During which week did Plant A grow most?

6) During which week did Plant B grow least?

7) Were the two plants of the same height during any week shown here? Specify.

The following graph shows the temperature forecast and the actual temperature for each day of a week.

1) On which days was the forecast temperature the same as the actual temperature?

2) What was the maximum forecast temperature during the week?

3) What was the minimum actual temperature during the week?

4) On which day did the actual temperature differ the most from the forecast temperature?

Use the tables below to draw linear graphs

The number of days a hill side city received snow in different years.

Year |
2003 | 2004 | 2005 | 2006 |

Days |
8 | 10 | 5 | 12 |

Use the tables below to draw linear graphs.

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

Year |
2003 | 2004 | 2005 | 2006 | 2007 |

Number of men |
12 | 12.5 | 13 | 13.2 | 13.5 |

Number of women |
11.3 | 11.9 | 13 | 13.6 | 12.8 |

A courier-person cycles from a town to a neighboring suburban area to deliver a parcel to a merchant. His distance from the town at different times is shown by the following graph.

1) What is the scale taken for the time axis?

2) How much time did the person take for the travel?

3) How far is the place of the merchant from the town?

4) Did the person stop on his way? Explain.

5) During which period did he ride fastest?

Can there be a time temperature graph as follows? Justify you’re answer:

Can there be a time-temperature graph as follows? Justify your answer

Can there be a time-temperature graph as follows? Justify your answer

Can there be a time temperature graph as follows? Justify you’re answer:

#### Chapter 15: Introduction to Graphs Exercise 15.20 solutions [Page 243]

Plot the following points on a graph sheet. Verify if they lie on a line

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

Plot the following points on a graph sheet. Verify if they lie on a line

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

Plot the following points on a graph sheet. Verify if they lie on a line

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

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.

Write the coordinates of the vertices of each of these adjoining figures.

State whether True or False. Correct those are false.

A point whose *x* coordinate is zero and *y*-coordinate is non-zero will lie on the *y*-axis.

True

False

State whether True or False. Correct those are false.

A point whose *y* coordinate is zero and *x*-coordinate is 5 will lie on *y*-axis.

True

False

State whether True or False. Correct those are false.

The coordinates of the origin are (0, 0).

True

False

#### Chapter 15: Introduction to Graphs Exercise 15.30 solutions [Pages 247 - 248]

Draw the graphs for the following tables of values, with suitable scales on the axes.

Cost of apples

Number of apples |
1 | 2 | 3 | 4 | 5 |

Cost (in Rs) |
5 | 10 | 15 | 20 | 25 |

Draw the graphs for the following tables of values, with suitable scales on the axes.

Distance travelled by a car

Time (in hours) |
6 a.m | 7 a.m | 8 a.m | 9 a.m |

Distance (in km) |
40 | 80 | 120 | 160 |

1) How much distance did the car cover during the period 7.30 a.m. to 8 a.m.?

2) What was the time when the car had covered a distance of 100 km since its start?

Draw the graphs for the following tables of values, with suitable scales on the axes.

Interest on deposits for a year:

Deposit (in Rs) |
1000 | 2000 | 3000 | 4000 | 5000 |

Simple interest (in Rs) |
80 | 160 | 240 | 320 | 400 |

1) Does the graph pass through the origin?

2) Use the graph to find the interest on Rs 2500 for a year:

3) To get an interest of Rs 280 per year, how much money should be deposited?

Draw a graph for the following.

Side of square (in cm) |
2 | 3 | 3.5 | 5 | 5 |

Perimeter (in cm) |
8 | 12 | 14 | 20 | 24 |

Is it a linear graph?

Draw a graph for the following.

Side of square (in cm) |
2 | 3 | 4 | 5 | 6 |

Area (in cm^{2}) |
4 | 9 | 16 | 25 | 36 |

Is it a linear graph?

## Chapter 15: Introduction to Graphs

#### NCERT Mathematics Class 8

#### Textbook solutions for Class 8

## NCERT solutions for Class 8 Mathematics chapter 15 - Introduction to Graphs

NCERT solutions for Class 8 Maths chapter 15 (Introduction to Graphs) include all questions with solution and detail explanation. This will clear students doubts about any question and improve application skills while preparing for board exams. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. Shaalaa.com has the CBSE Mathematics Textbook for Class 8 solutions in a manner that help students grasp basic concepts better and faster.

Further, we at Shaalaa.com are providing such solutions so that students can prepare for written exams. NCERT textbook solutions can be a core help for self-study and acts as a perfect self-help guidance for students.

Concepts covered in Class 8 Mathematics chapter 15 Introduction to Graphs are Concept of Bar Graph, Concept of Pie Graph (Or a Circle-graph), Concept of Histogram, Concept of a Line Graph, Some Applications, Linear Graphs - Location of a Point, Linear Graphs - Coordinates.

Using NCERT Class 8 solutions Introduction to Graphs exercise by students are an easy way to prepare for the exams, as they involve solutions arranged chapter-wise also page wise. The questions involved in NCERT Solutions are important questions that can be asked in the final exam. Maximum students of CBSE Class 8 prefer NCERT Textbook Solutions to score more in exam.

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