Introduction to Graphs Class 8 Notes CBSE Maths Chapter 15 (Free PDF Download)

• Data presented in a graphical format is easier to comprehend. 

1. To show comparisons between categories, a bar graph is employed.

2. To compare portions of a whole, a pie graph is employed.

3. A histogram is a bar graph with data displayed in intervals.

• A line graph depicts data that is constantly changing throughout time.

• A linear graph is a graph that consists of a single continuous line.

• The $\text{x}$ -coordinate and $\text{y}$ -coordinate are required to fix a point on the graph sheet.

• A graph depicts the relationship between the dependent and independent variables.

• A Bar Graph:

• A graphical representation of numerical data made out of uniformly sized bars (rectangles) with equal spacing. 

• Each bar's length (or height) symbolises the provided number.

• A Pie Graph:

• A pie graph is a visual representation of how sections of a whole are compared. 

• The sectors of the circle symbolise the numerous observations or components.

• Histogram:

A histogram is a form of bar diagram in which the class intervals are shown on the horizontal axis and the heights of the bars (rectangles) represent the frequency of the class interval, but there is no gap between the bars because the class intervals are not separated by a gap.

• Linear Graph:

A line graph with all of the line segments forming one continuous line.

• Coordinates:

An ordered pair of numbers represents a point on the Cartesian plane.

• Ordered Pair:

A set of numbers in a predetermined arrangement.

Class 8 Maths Notes of Introduction to Graphs

Introduction to Graphs In Revision Notes Class 8 Maths Chapter 15

Graphs are basically the visual illustrations of the data gathered. Graphical representation enables us to showcase the trend of the data. These graphs are applicable in different fields and it is of great help to the people. There are various types of Graphs and each of these serves a specific purpose.

Points to Remember for Introduction to Graphs

• The x-coordinate of a point is actually the distance from the y-axis.

• The y-coordinate of a point is actually its distance from the x-axis.

• The coordinates of the origin in a graph are valued at (0, 0).

• The x-coordinate of each point on y-axis is 0

• The y-coordinate of each point on x-axis is 0

• A line graph that’s completely an unbroken line is called a linear graph.

• A bar graph helps to establish and express comparison among categories.

• A pie graph helps to compare parts of a whole.

• A line graph shows data that changes constantly over periods of time.

• A histogram is a bar graph that depicts data in intervals.

• To fix a point on the graph we require, x-coordinate and y-coordinate.

• The relationship between dependent variable and independent variable is displayed through a graph.

Types of Graph Represented in Class 8 Revision Notes Introduction to Graphs

1. Bar Graph

A bar graph is a kind of graph which is made to show comparisons between different categories. In this kind of graph, bars of uniform width are used to display the different quantities and their height is kept proportional to their respective values.

The below bar graph is representing the kind of pet people usually own. 

2. Double Bar Graph

This is almost similar to the bar graph, just that two types of data are shown here correspondingly. Usually, this form of graph is used to display a comparison between two data.

This Double bar graph shows the different sports preferred by male and female students Yellow bars show the sports liked by girls and red bars show the sports liked by boys . Hence we can easily compare the like and dislike of sports in average students.

3. Pie Chart

Also known as Circle Graph is used to represent the given data in the circular form. When the data is represented in a circular form, it is termed as a pie chart. A pie chart basically shows the part of a whole.

This pie chart shows the percentage of people who like particular fruits. From the given pie chart, we can easily obtain that the maximum number of people like bananas and the least number of people like peaches 

4. Line Graph

We use the line graph when we tend to see the changes continuously over a period of time.

Here the horizontal line (x-axis) displays the number of days and the vertical line (y-axis) displays the number of muffins sold on a particular day on every successive day.

By this line graph, we can easily understand the changes in the sale of muffins during these 7 days of a week. 

5. Linear Graphs

A whole unbroken line is what we call a Linear Graph.

6. Histogram

We can construct a histogram when we have grouped the data in the form of class intervals. It is also a kind of bar graph. The only difference is that there is no gap between the bars as this is a graph of continuous data.

This histogram shows the height of the trees.

Benefits of the Ch 15 Class 8 Maths Revision Notes 

The given introduction to graphs class 8 notes Pdf free download available at Vedantu will help you to understand the graphs better and the appropriate ways to use them. If you have any query regarding class 8 maths revision notes chapter 15, drop a comment at the Vedantu website and have your query resolved at the earliest. Features of Vedantu’s Revision Notes to mention are: