What is the Cartesian plane?
In case you are wondering why it's called that, this was named after the mathematician Rene Descartes. The Cartesian plane is defined by two perpendicular lines: the x axis (horizontal) and the y-axis (vertical). Using the axes, we can describe any point in all four quadrants using an ordered pair of numbers, written as (x,y). These ordered pairs of numbers are called coordinates.
The rule
To find coordinates, we use the x first then the y. The rule is: 'along the corridor and up the stairs'. Another way to remember: 'x is a cross, so it goes across'.
Origin
The origin is the point (0,0) in the middle of all four quadrants, where they all meet.
Four quadrants
Bringing the x and y axis past the origin (0,0) makes negative coordinates. The regions separated by the axes are called quadrants; there are four quadrants. Coordinates in these quadrants are still described with the x and y, but now the coordinates can be negative or positive.
The fancy names
Just in case you need to know, here are the fancy names for the axes (if you can remember them).
X: abcissa
Y: ordinate.
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Maths Revision
RandomMy funny and well-explained KS3 Maths Revision guide, derived from Bitesize. Still in progress, as I learn the nightmare called Maths by myself.
