Math Dictionary / Constant of Proportionality
Constant of Proportionality
The constant of proportionality is the constant ratio between two proportional quantities.
Ratios and ProportionsGrade 7Grade 8Algebra 1GEDSATACT
What it means
In y = kx, the number k is the constant of proportionality.
Also called: k value, proportional constant
Examples
| If y = 4x, k = 4 |
| If 3 notebooks cost $9, k = 3 dollars per notebook |
| A graph of a proportional relationship passes through the origin |
Common mistake
A proportional relationship must have a constant ratio and pass through the origin when graphed.
Try one
Question: In y = 6x, what is the constant of proportionality?
Show answer
6.