CBSE Class 8 Math, Introduction to Graphs

•   Pictorial and graphical representation are easier of understand.

•   Bar graphs and pie graphs are used for comparing categories and parts respectively.

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

•   A line graph displays data that change continuously over periods of time.

•   A line graph being wholly an unbroken line is called a linear graph.

•   For fixing a point the graph sheet we take two mutually perpendicular lines called axes.

•   The horizontal line of the axes is called the x-axis and the vertical line is called the y-axis.

        The purpose of drawing a graph is to show numerical facts in usual form so that they can be understood quickly, easily and clearly. We also know that a bar graph is used to show a comparison among categories. A bar graph may consists of two or more parallel horizontal or vertical bars of equal width.

        A pie-graph is used to compare various parts of a whole using a circle. A histogram is a bar-graph that shows data in intervals. It has adjacent bars over the intervals as shown below.

        A line-graph is called a linear-graph and it displays data that changes continuously over periods of time.