Y-Coordinates (Mathematics Glossary)
What Is the Y-Coordinate?The y-coordinate is the second number in the pair of numbers used to describe Cartesian coordinates.
For example, in the Cartesian coordinates (2,4), the y-coordinate is 4 (the number on the right):
What Does the Y-Coordinate Mean?The y-coordinate tells you how far up (or down) the vertical y-axis a point is on a graph (measured from the origin).
If a point has Cartesian coordinates (2,4), the point would be 4 units up the y-axis. The image below shows what we mean by a point being 4 units along the x-axis (measured from the origin):
Note: The y-axis is labelled with numbers (0, 1, 2, 3...) so you can measure how far up the point is.
The Y-Coordinate Can be Positive...If you go up the y-axis (above the x-axis), it is labelled with positive numbers (0, 1, 2, 3...).
The y-coordinate of any point above the x-axis is positive.
Imagine a point had an y-coordinate of 4. It would be 4 units above the y-axis:
...Or the Y-Coordinate Can be NegativeIf you go down the y-axis (below the x-axis), it is labelled with negative numbers (0, -1, -2, -3...).
The y-coordinate of any point below the x-axis is negative.
Imagine a point had an y-coordinate of -4. It would be 4 units below the x-axis:
Here's a second test on the y-coordinate.
Here's a third test on the y-coordinate.
Which Axis Is Which?The x is a cross - so the x-axis goes across!
The y-axis must go up.
The OriginThe point labelled with a 0 on the y-axis is called the origin.
What Are Cartesian Coordinates?Cartesian coordinates are used to describe the position of a point on a graph.
Cartesian coordinates work by measuring how far across and how far up the point is from the origin.