# The point where axis and axes meet

### The Coordinate Plane The axes intersect when both x and y are zero. The coordinates of the Begin at the point and follow a vertical line either up or down to the x-axis. There is your. The x and y axes are part of the Cartesian coordinate system, also The place where the x-axis and y-axis meet is at a zero value on both the x. The straight line on the graph below intercepts the two coordinate axes. The point where the line crosses the x-axis is called the [x-intercept]. . Joe needs to do is connect the points with a line, and then extend the line until it meets the x-axis.

The first part of the alphabet was used to designate known values. A Euclidean plane with a chosen Cartesian coordinate system is called a Cartesian plane. In a Cartesian plane one can define canonical representatives of certain geometric figures, such as the unit circle with radius equal to the length unit, and center at the originthe unit square whose diagonal has endpoints at 0, 0 and 1, 1the unit hyperbolaand so on.

The two axes divide the plane into four right anglescalled quadrant. The quadrants may be named or numbered in various ways, but the quadrant where all coordinates are positive is usually called the first quadrant.

If the coordinates of a point are x, ythen its distances from the X-axis and from the Y-axis are y and xrespectively; where The tick marks on the axes are one length unit apart.

## Coordinate system and ordered pairs

A Cartesian coordinate system for a three-dimensional space consists of an ordered triplet of lines the axes that go through a common point the originand are pair-wise perpendicular; a orientation for each axis; and a single unit of length for all three axes. As in the two-dimensional case, each axis becomes a number line. For any point P of space, one considers a plane through P perpendicular to each coordinate axis, and interprets the point where that plane cuts the axis as a number. The Cartesian coordinates of P are those three numbers, in the chosen order. The reverse construction determines the point P given its three coordinates. Alternatively, each coordinate of a point P can be taken as the distance from P to the plane defined by the other two axes, with the sign determined by the orientation of the corresponding axis. Each point is identified by both an x and a y coordinate. In this unit you will learn how to find both coordinates for any point. You will also learn the correct notation for labeling the coordinates of a point. You will first begin by identifying the x-coordinateof a point. Identifying the x-coordinate The x-coordinate of a point is the value that tells you how far from the origin the point is on the horizontal, or x-axis.

### Coordinate Axes

To find the x-coordinate of a point on a graph: Draw a straight line from the point directly to the x-axis.

The number where the line hits the x-axis is the value of the x-coordinate. At the right is a graph with two points, B and D. The x-coordinate of point B is The x-coordinate of point D is Identifying the y-coordinate As we already mentioned, each point is defined by two coordinates, the x and the y coordinate.

### Cartesian coordinate system - Wikipedia

Now that you know how to find the x-coordinate of a point, you have to be able to find the y-coordinate. The y-coordinate of a point is the value that tells you how far from the origin the point is on the vertical, or y-axis. To find the y-coordinate of a point on a graph: Draw a straight line from the point directly to the y-axis. The number where the line hits the axis is the value of the y-coordinate.

Looking back at the graph with our points B and D, we now identify the y-coordinate for each. The y-coordinate of point B is The y-coordinate of point D is Notation for Identifying Points Once you have the coordinates of a point you can use the ordered pair notation for labeling points.

The notation is simple. If not, you will be told the coordinates of the point on which you have clicked, and you can try again.

• Coordinate Axes
• Cartesian coordinate system

Continue this way until you finish the list. To get a new list, click on "New" again. Plotting Points In the next activity you will practice identifying the coordinates of points that are graphed. Each time you click on "New", there will appear some points in the graph on the left, and a list of coordinate pairs on the right. One of the points on the graph will appear in red; this is the one that you are to identify.

If you click on the correct pair of coordinates, a different point will become red; this is the next one to identify.

If you click on the wrong pair, you may try again.