Skill: Locate points in all four quadrants

A coordinate plane has two perpendicular number lines:

• The horizontal axis is the $x$-axis.
• The vertical axis is the $y$-axis.
• They meet at the origin, $(0,0)$.

An ordered pair is written as $(x,y)$. Always move left or right first using $x$, then up or down using $y$.

The signs tell you the quadrant:

$$\begin{array}{c|c} \text{Quadrant} & \text{Signs of }(x,y)\\ \hline \text{I} & (+,+)\\ \text{II} & (-,+)\\ \text{III} & (-,-)\\ \text{IV} & (+,-) \end{array}$$

Example: Locate the point $(-3,2)$

1. The $x$-coordinate is $-3$. Start at the origin and move 3 units left.
2. The $y$-coordinate is $2$. From there, move 2 units up.
3. The point is $(-3,2)$.
4. Its signs are $(-,+)$, so it is in Quadrant II.

Remember: if a coordinate is $0$, the point is on an axis, not in a quadrant. For example, $(0,4)$ is on the $y$-axis, and $(-2,0)$ is on the $x$-axis.