The Lesson
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 Negative
If 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:
Which Axis Is Which?
The
x is a cross - so the
x-axis goes across!
The
y-axis must go up.
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