Slope is how steep a line is. Climb a mountain or roll down a ramp — slope tells you how much vertical you get per unit of horizontal.
Slope
m = (y₂ − y₁) / (x₂ − x₁)
rise over run, between any two points on the line
What the value means
- Positive — line climbs left to right.
- Negative — line falls left to right.
- Zero — perfectly horizontal line.
- Undefined — vertical line (run is zero, so dividing by zero).
Try it
Slope from (1, 2) to (4, 8)?
(8 − 2) / (4 − 1) = 6/3 = 2. Up 2 for every 1 across.