Slope (Gradient) of a Straight Line
The Slope (also called Gradient) of a straight line shows how steep a straight line is.
Calculate
The method to calculate the slope is:
Divide the change in height by the change in horizontal distance
| Slope = |
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Examples:
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So the slope is equal to 1 |
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| slope = |
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= 2 | |||
(The line is steeper, and so the slope is larger)
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| slope = |
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= 0.6 | ||||
(The line is less steep, and so the slope is smaller)
Positive or Negative?
Important:
- Starting from the left end of the line going across to the right is positive
(but going across to the left is negative). - Up is positive, and down is negative
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| slope = |
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= –2 | |||
(That line goes down as you move along, so it has a negative slope.)
Straight Across
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| slope = |
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= 0 | |||
(A line that goes straight across has a slope of zero.)
Straight Up and Down
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| slope = |
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= undefined | |||
That last one is a bit tricky ... you can't divide by zero,
so a "straight up and down" 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