Plotting Coordinates On A Grid

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Hi there. In this education post, I cover the topic of plotting coordinates on a grid. This topic can be taught to students from grade six to eight. It can also be taught to younger students in grade three to five which would be a bit ambitious.

Screenshots of the plotted points are on Desmos.


Pixabay Image Source

 

Topics


  • Points In The Positive (x,y) Quadrant
  • Points With The Full Grid
  • Summary

 

Points In The Positive (x,y) Quadrant


Instead of going right into the full quadrant, I start with the positive x and positive y quadrant. The point (x, y) refers to a single point on the Cartesian co-ordinate grid. The value of x refers to the horizontal (left to right) position on the grid while the value of y is for the vertical position on the grid.

 

Origin Point

One of the most important points is the origin. The origin has a point of (0, 0). This point is the intersection of the horizontal x-axis and the vertical y-axis.

origin_point.PNG

 

Example One

Mark the point (3, 0) on the grid.

Start from the origin point (0, 0). The first value is a three which means three units to the right from the origin.

01_example1.PNG

 

Example Two

Plot the point (0, 7).

From the origin, do not move any units left or right. The seven from the y-value in (0, 7) means to move up 7 units up.

01_example2.PNG

 

Example Three

Plot the point (2, 5) on the grid.

With this case, move 2 units right and five units up from the origin (0, 0). You can also do the other order where you move up 5 units and move 2 units right.

01_example3.PNG

 

Points With The Full Grid


The points so far dealt with positive numbers for x and y. The inclusion of negative numbers gives the full grid. In the full grid we have four quadrants.

  • Top right is positive x, positive y
  • Top left is negative x, positive y
  • Bottom left is negative x, negative y
  • Bottom right is positive x, negative y.

 

Example One

On the full grid, plot (-2, 3).

The x-value in (-2, 3) is -2. Negative two for x means move two units left from the origin. For vertical movement, a y-value of 3 means move up 3 units.

02_example1.PNG

 

Example Two

Plot (1, -5) on the full grid.

With (1, -5), move one unit to the right from the origin (0, 0). Afterwards move down 5 units to obtain the point (1, -5).

02_example2.PNG

 

Example Three

With the full grid, plot the points (-1, -2) and (0, -3).

The second point of (0, -3) is not too hard to plot. It is no left or right movement and down 3 units. For the (-1, -2), move left 1 unit from the origin and then down 2 units.

02_example3.PNG

 

Summary


  1. Positive x means go right.
  2. Negative x means go left
  3. Positive y is up.
  4. Negative y is down.
  5. Zero for x means no movement left or right.
  6. Zero for y means no movement up or down.

 


Pixabay Image Source

Thank you for reading.

Posted with STEMGeeks



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2 comments
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I remember plotting with graphing paper.

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Same here. With graphing paper, lined paper and blank paper (worst case).

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