proportional to
If A is proportional to B then A is equal to a constant times B.
| Notes: | ||
| 1. | The constant mentioned above is called the constant of proportionality. A lot of people think that A being proportional to B simply means that when B increases, A increases.While A does increase with an increase in B in the case of a positive constant of proporitonality, the fact that an increase in B results in an increase in A does not mean that A is proportional to B. Suppose for instance that A=5B2. If A increases, B increases. But A is not equal to a constant times B. Thus A is not proportional to B. | |
| 2. | The doubling test can be a convenient check on whether A is propotional to B. If the relationship between A and B is such that, for any starting value of B, doubling B results in a doubling of A, then A is proportional to B. | |