The Coordinate Plane

The coordinate plane is a two-dimensional surface for graphing points and lines.

Structure

The coordinate plane has two axes:

• x-axis: Horizontal line (left-right)
• y-axis: Vertical line (up-down)
• Origin: The point where they cross $(0, 0)$

Quadrants

The axes divide the plane into 4 quadrants:

Ordered Pairs

Points are written as $(x, y)$:

• First number: horizontal position (x)
• Second number: vertical position (y)

Examples

$(3, 2)$: Right 3, Up 2 $(-4, 1)$: Left 4, Up 1 $(0, -5)$: On y-axis, Down 5 $(2, 0)$: Right 2, On x-axis

Plotting Points

To plot $(4, 3)$:

1. Start at the origin $(0, 0)$
2. Move right 4 units (positive x)
3. Move up 3 units (positive y)
4. Mark the point!

To plot $(-2, -4)$:

1. Start at the origin
2. Move left 2 units (negative x)
3. Move down 4 units (negative y)
4. Mark the point!