Introduction to the coordinate Plane

What is the coordinate plane? Coordinate plane: The plane formed by two perpendicular lines called the x-axis and y- axis. x-axis: the horizontal number line. y-axis: the vertical number line.

What is the coordinate plane?

Ordered pairs Ordered pair: a pair of numbers that represents a unique point in the coordinate plane. The first value is the x coordinate and the second value is the y coordinate. Ex. 1: (2, 3) → 2 is the x coordinate and 3 is the y coordinate

The origin Origin: the center of the coordinate plane. It has coordinates (0, 0). It is the point where we always start when we are graphing.

How do I plot a point? To graph a point in the coordinate plane start at the origin. Look first at the x coordinate. If the x coordinate is positive, move that many spaces to the right. If the x coordinate is negative, move that many spaces to the left. From your x coordinate location look at the y coordinate. If the y coordinate is positive, go up that many spaces. If the y coordinate is negative, go down that many spaces.

Let’s try plotting

Let’s try plotting

Name the coordinates of a point

Name the coordinates of a point

Name the coordinates of a point

Name the coordinates of a point

What quadrant is a point in? Quadrant I (x, y) Positive x and positive y Quadrant II (-x, y) Negative x and positive y Quadrant III (-x, -y) Negative x and negative y Quadrant IV (x, -y) Positive x and negative y Points on the x-axis or y-axis do not belong to any quadrant.

Let’s try a few D F E A C B

Let’s try a few D X-axis F E Quadrant IV Quadrant III A Quadrant I Y-axis C Quadrant II B

Name the coordinates of a point

Which quadrant? (3, -2) (-1, 4) (-5, 0) (-4, -4) (0, -5)

Which quadrant? (3, -2) Quadrant IV (-1, 4) Quadrant II (-5, 0) x-axis (-4, -4) Quadrant III (0, -5) y-axis Now list the coordinates for one point that is in Quadrant I.