Lesson 3.3: Slopes of Lines
Key Concepts: Slopes of Lines
Slope
The slope of a Line measures its steepness and direction. Given two points (x₁, y₁) and (x₂, y₂):
m = (y₂ − y₁) / (x₂ − x₁)
Types of Slope
- Positive slope: Line rises from left to right.
- Negative slope: Line falls from left to right.
- Zero slope: Horizontal Line (y values constant).
- Undefined slope: Vertical Line (x values constant, division by zero).
Parallel and Perpendicular Slopes
- Parallel lines: Same slope (m₁ = m₂).
- Perpendicular lines: Slopes are negative reciprocals (m₁ × m₂ = −1).