Difference between revisions of "Directly Proportional"
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===About Direct Proportionality=== | ===About Direct Proportionality=== | ||
− | : A [[Scatter Graph|scatter graph]] showing a '''directly proportional''' relationship has a [[linear]] [[gradient]] that passes through zero | + | : A [[Scatter Graph|scatter graph]] showing a '''directly proportional''' relationship has line with a [[linear]] [[gradient]] that passes through zero (it has a [[y-intercept]] of zero). |
: On a [[proportional]] [[Scatter Graph|scatter graph]] when one [[variable]] doubles, the other doubles or when one triples the other triples. | : On a [[proportional]] [[Scatter Graph|scatter graph]] when one [[variable]] doubles, the other doubles or when one triples the other triples. | ||
: When two variables are '''directly proportional''' when any value for y is divided by its corresponding value for x it will always give a constant value. | : When two variables are '''directly proportional''' when any value for y is divided by its corresponding value for x it will always give a constant value. | ||
: Two variables are said to be '''directly proportional''' when they always vary by the same ratio. | : Two variables are said to be '''directly proportional''' when they always vary by the same ratio. | ||
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+ | ===Exam Marks=== | ||
+ | : Straight line [1 mark] | ||
+ | : Passing through zero / passing through the origin [1 mark] | ||
===Examples=== | ===Examples=== |
Latest revision as of 15:24, 5 December 2021
Contents
Key Stage 4
Meaning
When two variables are directly proportional when one variable is multiplied by a factor, the other variable is multiplied by the same factor.
About Direct Proportionality
- A scatter graph showing a directly proportional relationship has line with a linear gradient that passes through zero (it has a y-intercept of zero).
- On a proportional scatter graph when one variable doubles, the other doubles or when one triples the other triples.
- When two variables are directly proportional when any value for y is divided by its corresponding value for x it will always give a constant value.
- Two variables are said to be directly proportional when they always vary by the same ratio.
Exam Marks
- Straight line [1 mark]
- Passing through zero / passing through the origin [1 mark]
Examples
This scatter graph shows a linear relationship that is directly proportional where x doubles, y doubles.
\(y = mx\) Where m, the gradient, is positive. |
References
AQA
- Directly proportional, pages 158-159, 282, GCSE Physics; Third Edition, Oxford University Press, AQA