- The Slope of a line (m) is a description of a line with respect to its direction and steepness
- A line that increases or goes up moving left to right ( / ) has a positive Slope (m > 0)
- A line that decreases or goes down moving left to right ( \ ) has a negative Slope (m < 0)
- The Slope of a horizontal line (↔) is equal to zero (m = 0)
- The Slope of a vertical line (↑) is undefined (m is undefined)
- Two lines are parallel ( = ) if they have the same Slope (m1 = m2 )
- Note: Vertical lines are parallel to each other
- Two lines are perpendicular ( + ) if the product of their Slopes is equal to -1 (m1 * m2 = -1)
- Note: Horizontal and vertical lines are perpendicular to each other
- m could be found given the coordinates of two points on the line