How to Read Graphs and Charts?

Graph is a pictorial representation of an expression. Expression shows relation between two or more variables. In other words, a graph can be stated as a representation of a function which expresses relationship among two or more than two variables. Graphs may be straight line, parabolic, hyperbolic, inverse graph etc.
Let’s understand how to read graphs and charts.
Y = m x + c. When we substitute x = 0 then y = c, when x = 1 then y = m + c, when x = 2 then y = 2m +c and so on. So it is clear 'x' increases, 'y' also increases for any value of ‘m’ and ‘c’.
This can be plotted as shown below.
 
 
 
Here in above graph, relationship between 'x' and 'y' is shown. In this graph, 'c' is representing a constant value by which the graph has been shifted from the origin on the y – axis. Origin is the Intersection Point of x – axis and y – axis. Term ‘m’ represents the Slope. This is given by Ratio of ‘dy’ to ‘dx’. dy represents small change in values on y - Axis and ‘dx’ shows small change in values on
x – Axis. Chart can be defined as Graphical representation of Functions or any type of data such as Percentage of men, women, children etc. as a part of whole population counting. Let's consider a pie chart to understand how to read it.
 
 
 
A pie (circle) chart mainly has three parts. These are title, sectors and label. Here in the above example, the title of the chart is “Various Percentages Among Total Students of School”
The Circle or pie graph above shows the percentage of students among total achieved marks. There are four sectors.
Sector A:    10% students are above 80%
Sector B:   15tudents achieved between 36% and 49%
Sector C:    50% students achieved 61% - 75%
Sector D:   25% students achieved 50% - 60%.