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How To Plot Simple Graph & Find The Slope

How To Plot Simple Graph & Find The Slope

What is Graph and what are the areas of Application?

When it comes to data analysis and comparisons graph plays vital roles. Graph is one tool use in engineering and science related activities to make clear distinction between two divers records. It goes beyond comparison to provision of other vital information such as numeric values, age, and lots more.

It is a common thing to come across graphs in some of your daily activities if you are an engineer or in a related profession or science student at any level. Graph and chart have similarities, but the term chart is use for more advance and complex graph. A simple graph is the one that compares two values in the horizontal axis and vertical axis.

In mathematics, graph is use in solving quadratic equation and to solve some of the algebra problems. Graph is something you cannot avoid as a science student the best you can do is to spend time and go through this post to gain more information about graph and how to plot simple graphs.


The vertical axis of a simple graph is known as Y-Axis while that of the horizontal axis is known as X-Axis. The two axis are two drawn lines in vertical and horizontal axis. The two line meet at a point known as zero point in the graph when plotting any value in the graph.

Graph can be any size and the size is determined by the length of the lines carrying the values. The values that graph need to carry equally determines the size. However, higher values can be contained in small graph by increasing the range of values within a line.

Assuming you have values that range from 1 to 1000 and values that range from 1 to 100 and want to plot the two in a graph for comparison. Let us assume you are using the Y-Axis for the 1 to 100 values and the X-axis for the 1 to 100 value. The unit range for the y-axis will be higher that the unit range for X-axis. To make the Y-axis line shorter and equal with the X-axis, you can use 10mm for 100unit in Y-axis and use 10mm for 10units in X-axis. This method will make the graph shorter and easier to plot. See the example below:

A student was asked to plot a simple graph for number of male and female in a group chat. The number of male is 1000 and the number female is 100.

To plot this type of data in a graph you need to find common dividing ratio that can give uniform values in equal ratio. Therefore, using 1000/100 = 10 to make an equal division of the values in 10th units, the table below was prepared.



The table above was made to make the plotting of graph possible. So when trying to plot graph you need to prepare a table of the data given in the possible ratio that the graph will be plotted.

Step 1.

Draw a straight line horizontal and vertical lines on your graph sheet or on a plane sheet of paper. Let the two lines meet at the point labeled “0” which is your zero point/value for both axis.

Using your ruler, make out 10mm apart on the vertical line up to ten places and repeat the same on the horizontal line. The image below shows how your work should look like.


Step 2.

With your ruler start to join the vertical line (Y-axis) values to the horizontal line (X-axis) values as shown below.




Each values linked together must correspond to the table you have prepared earlier.



Step 3.

Make a straight line from the zero point of the graph to join all the points of intersection of all the values. Though not all the points of intersection will fall on the part of the line, you can still use the line for your calculations. The photo below shows how your work should look.



Step 4.

Calculate the slope of the graph by picking any two points of intersection on the X-axis and another two points of intersection on the Y-axis. The difference in the larger value minus lesser value will become the value of each axis.

To get the slope, divide the value obtained from Y-axis with the value obtained from the X-axis the result is the slope of the graph.



The image below shows how to possibly calculate your slope. However, some graphs with higher values on the horizontal axis will give you decimal answer, in that case, the slope of this graph can be assumed to be 0.1

An accurate graph will maintain a consistence unit range meant for both axis. This helps the data obtained to be accurately plotted and accurate result obtained. If you make mistake in placing correct values in any of the axis, unfortunately the graph will be inaccurate and definitely you will get in accurate result in any analysis from the graph.




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