The Coordinate Plane
Grades 6–8 Geometry Graphs Algebra
Two number lines crossed at right angles give the coordinate plane: x runs sideways, y runs up-down, and they meet at the origin (0, 0). Every point gets an address: (x, y) — x first, then y. Always.
The four quadrants
- I (+x, +y) — top right
- II (−x, +y) — top left
- III (−x, −y) — bottom left
- IV (+x, −y) — bottom right
Distance between points
Same row or column → count the squares. Diagonal → the Pythagorean theorem does it (next unit):
(1, 2) to (7, 2): 7 − 1 = 6 units
(4, 5) to (4, −1): 5 − (−1) = 6 units
Why it matters here
The coordinate plane is where algebra meets geometry — every
line, curve, and shape you've graphed lives on it. It's also how
every screen on Earth addresses pixels.
Practice
The point (−4, 7) sits in quadrant:
Distance from (2, 3) to (7, 3): ___ units
Distance from (1, −2) to (1, 6): ___ units
The origin is:
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