The slope of a line is a measure of its steepness, and it can be used to describe the direction of the line. On a four-quadrant chart, the slope of a line is determined by the ratio of the change in the y-coordinate to the change in the x-coordinate.
The slope can be positive, negative, zero, or undefined. A positive slope indicates that the line is rising from left to right, while a negative slope indicates that the line is falling from left to right. A slope of zero indicates that the line is horizontal, while an undefined slope indicates that the line is vertical.