Solve
Step
Check 
If x = 12, then y = 4.
y = 4
| Find the constant of proportionality. y is directly proportional to x. If x = 12, then y = 4. |
|
Solve |
Step |
Check |
| The goal is to find k, the constant. |
|
|
| y = kx | Use the formula for direct variation |
If x = 12, then y = 4. |
| If x = 12, then y = 4. | Given |
|
| 4 = k(12) | Plug in x and y | |
| 4 = 12k | Divide by 12 |
y = 4 |
|
|
constant of proportionality | |
| Plug 1/3 in formula for k | ||
|
|
Done | |
| Now we have a formula that can be used to find values for y for specific values of x. | ||