Definition: The coordinate plane is a flat grid formed by a horizontal x-axis and a vertical y-axis that cross at the origin, used to locate points with ordered pairs.
What is the coordinate plane?
It is a two-dimensional grid made from two perpendicular number lines. The horizontal line is the x-axis, the vertical line is the y-axis, and they meet at the origin (0, 0).
How do you read a point?
Each point has an ordered pair (x, y). The first number tells you how far to move right (positive) or left (negative). The second tells you how far to move up (positive) or down (negative). To plot (-4, 3), start at the origin, go 4 left, then 3 up.
Why is it useful?
Maps, video game screens, and graphs of equations all use coordinates. Mathbot navigates a warehouse floor by coordinates, and distances along a horizontal or vertical segment come from subtracting or adding the matching coordinates.
What is the classic error?
Swapping the order. The point (2, 7) and the point (7, 2) are in different places. Remember the alphabet: x comes before y, and you walk along the floor before you climb.