What gradient means
- Positive gradient: the line goes up from left to right.
- Negative gradient: it goes down from left to right.
- Zero: a horizontal line.
- Undefined: a vertical line (you can't divide by a run of 0).
The bigger the number (ignoring the sign), the steeper the line.
From two points
Worked example
Find the gradient of the line through and .
It doesn't matter which point you call the first, as long as you keep the and from the same point together.
Gradient calculator (with working)
Enter two points. You’ll get the gradient, the equation of the line, the midpoint and the distance between them, with every step.
From a graph
Pick two points where the line crosses grid corners exactly. Count the rise (up is positive, down is negative), then the run (left to right), and divide.
If the line goes down 3 squares for every 2 across, the gradient is .
From an equation
In , is the gradient and is the y-intercept.
- : gradient .
- : rearrange to , so the gradient is .
Always get on its own first.
Parallel and perpendicular lines (Year 10)
- Parallel lines have the same gradient.
- Perpendicular lines have gradients that multiply to : . Flip the fraction and change the sign. Perpendicular to is .
Practice questions with answers
Try each one before you open the answer.
Find the gradient through and .
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Find the gradient through and .
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Find the gradient through and .
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Find the gradient through and .
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(a horizontal line)
What is the gradient of ?
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What is the gradient of ?
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Rearrange: , so
A line is perpendicular to one with gradient . What is its gradient?
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The negative reciprocal:
Gradient by year level
Following the Victorian Curriculum 2.0. Schools sequence topics differently, so check your course.
Year 8
Linear equations and graphs
Linear graphs and gradient as rise over run.
Year 9
Coordinate geometry
The gradient formula, midpoint and distance between two points.
Year 10
Coordinate geometry
Equations of lines, parallel and perpendicular gradients.