2.2 Plotting Points and Reading Coordinates
On page 2.1, we plotted a point which had the value 4 on the xaxis and 2 on the yaxis, the coordinates 4 and 2. When you state a point’s position in a coordinate system, you usually always begin with the horizontal axis, the xaxis. After that you indicate the yvalue, the position on the yaxis. This is written (4, 2) and can be read as: 
 ”the point 4, 2”
 ”a point with the coordinates 4 and 2”
 ”a point with the xcoordinate 4 and ycoordinate 2”.

You usually also name the point with an upper case letter. If we give the point (4, 2) the name P, it would be written P(4, 2). 


If you are going to plot a point in a coordinate system, you can use the method below. We will take a new example where the
xcoordinate is 4 and the ycoordinate is 2, (4, 2).
1. We begin with the xcoordinate, the horizontal axis. Because the
xaxis is 4, we look for the 4 on the xaxis. 

We know that our point will lay somewhere along this dotted line because it shows where the xvalue is 4. We know that the yvalue is 2, and then can even plot that in the coordinate system. 

Now you have two dotted lines, one that shows 4 on the xaxis and another that shows 2 on the yaxis. Both of these lines intersect at a point. The points position is (4, 2) because we always begin by indicating the xvalue.
These red lines which we have drawn in order to be able to see where the point ends up are usually not drawn when we indicate a coordinate. 

