If a relationship exists between two variables such that their ratio is a
non-zero constant, the relationship is referred to as a direct variation.
The constant is often referred to as the
constant of variation, or constant of proportionality.
If two variables, say x and y, are in direct variation, then y = kx for some constant k.
In this relationship, we say y varies directly with x or y varies directly as x.
Since
y varies directly with
x, the relationship can be represented by an equation of the form
y = k
x, where k is some constant.
The constant, k, is referred to as the constant of proportionality.
Use the given values to solve for k.
| y | = | kx |
| 16 | = | k(8) |
| 16 ÷ 8 | = | k(8) ÷ 8 |
| 2 | = | k |
Since
y varies directly with
x, the relationship can be represented by an equation of the form
y = k
x, where k is some constant.
The constant, k, is referred to as the constant of variation.
Use the given values to solve for
x.
| y | = | kx |
| 14 | = | 2x |
| 14 ÷ 2 | = | 2x ÷ 2 |
| 7 | = | x |
8th Grade Math - Proportional vs. Not Proportional Lesson