Y-coordinate

Definition

The y-coordinate of a point in a Cartesian coordinate system indicates its vertical position relative to the x-axis. It is the second number in an ordered pair (x, y) and represents how far up or down the point is from the origin.

5 Must Know Facts For Your Next Test

1. The y-coordinate is always written second in an ordered pair, following the x-coordinate.
2. A positive y-coordinate means the point is above the x-axis, while a negative y-coordinate means it is below.
3. In equations of lines, such as $y = mx + b$, 'y' represents the y-coordinate for any given x value.
4. When plotting points on a graph, you move vertically according to the y-coordinate after moving horizontally according to the x-coordinate.
5. The y-intercept of a line occurs when the x-coordinate is zero; this means it is where the line crosses the y-axis.

Review Questions

• What does a positive y-coordinate indicate about a point's position?
• How do you determine where a line crosses the y-axis?
• In which part of an ordered pair can you find the y-coordinate?

Related terms

x-axis: The horizontal axis in a Cartesian coordinate system used as a reference line for measuring coordinates.

origin: The point (0,0) where the x-axis and y-axis intersect in a Cartesian coordinate system.

slope: A measure of how steep a line is, calculated as the ratio of rise over run between two points on the line.