Slope (Gradient) of a Straight Line

The Slope (also called Gradient) of a straight line shows how steep a straight line is.


To calculate the Slope:

Divide the change in height by the change in horizontal distance
Slope = Change in YChange in X   gradient



The Slope of this line = 3 3 = 1

So the Slope is equal to 1



The Slope of this line = 4 2 = 2

The line is steeper, and so the Slope is larger.



The Slope of this line = 3 5 = 0.6

The line is less steep, and so the Slope is smaller.


Positive or Negative?




Slope = −4 2 = −2

That line goes down as you move along, so it has a negative Slope.

Straight Across


Slope = 0 5 = 0

A line that goes straight across (Horizontal) has a Slope of zero.

Straight Up and Down


Slope = 3 0 = undefined

That last one is a bit tricky ... you can't divide by zero,
so a "straight up and down" (vertical) line's Slope is "undefined".

Rise and Run

Sometimes the horizontal change is called "run", and the vertical change is called "rise" or "fall":


They are just different words, none of the calculations change.