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Coordinate Plane
A two-dimensional surface on which points are plotted and located by their x and y coordinates
Try this
Drag the point A. As you drag note the two numbers that define it's position on the plane.
Drag the origin to reposition the axes.
The coordinate plane is a two-dimensional surface on which we can plot points, lines and curves. It has two scales, called the x-axis and y-axis, at right angles to each other. The plural of axis is 'axes' (pronounced "AXE-ease"). X axisThe horizontal scale is called the x-axis and is usually drawn with the zero point in the middle. As you go to the right on the scale the values get larger and are positive. As you go to the left, they get larger but are negative.Y axisThe vertical scale is called the y-axis and is also usually drawn with the zero point in the middle. As you go up from zero the numbers are increasing in a positive direction. As you go down from zero they increase but are negative.OriginThe point where the two axes cross (at zero on both scales) is called the origin. In the figure above you can drag the origin point to reposition it to a more suitable location at any time.Quadrants
In the diagram above, you can drag the origin all the way into any corner and display just one quadrant at a time if you wish. Things to tryIn the figure at the top of the page, first press 'reset'.
Other Coordinate Geometry entries
(C) 2007 Copyright John Page
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When the origin is in the center of the plane, they divide it into four areas called quadrants.
The first quadrant, by convention, is the top right, and then they go around counter-clockwise.
In the diagram above they are labelled Quadrant 1,2 etc. It is conventional to label them with numerals
but we talk about them as "first, second, third, and fourth quadrant".