Coordinates on the Cartesian Plane
The Cartesian plane uses two number lines (axes) at right angles to locate any point. Every point is described by an ordered pair (x, y) where x is horizontal and y is vertical.
What You Need to Know
Key Concept Diagram
The x-axis is horizontal; the y-axis is vertical; they meet at the origin (0, 0)
Coordinates are written as ordered pairs: (x, y) — always x first, then y
Positive x is to the right; negative x is to the left; positive y is up; negative y is down
The four quadrants are numbered I (top-right), II (top-left), III (bottom-left), IV (bottom-right)
Key Vocabulary
Origin
The point (0, 0) where the x-axis and y-axis intersect
Ordered pair
A pair of numbers (x, y) that gives the position of a point on the Cartesian plane
x-axis
The horizontal number line on the Cartesian plane
y-axis
The vertical number line on the Cartesian plane
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
What are the coordinates of the origin?
Question 2
A point is at (3, -2). In which quadrant does it lie?
Question 3
Which point is 4 units to the left of the origin and 3 units up?
Key Concepts Summary
- ●The x-axis is horizontal; the y-axis is vertical; they meet at the origin (0, 0)
- ●Coordinates are written as ordered pairs: (x, y) — always x first, then y
- ●Positive x is to the right; negative x is to the left; positive y is up; negative y is down
- ●The four quadrants are numbered I (top-right), II (top-left), III (bottom-left), IV (bottom-right)