The right answer is the constant of proportionality
If two variables are related and this relationship is that there is a constant ratio between them, then we are talking about proportionality. There are two types of proportionality.
1) Direct Proportionality:
In a mathematical language this is given by this equation:
\(y=kx\)
where \(k\) is in fact this constant of proportionality. If \(x\) increases, \(y\) also increases at the same rate. On the other hand, If \(x\) decreases, \(y\) also decreases at the same rate.
2) Inverse Proportionality:
In a mathematical language this is given by this equation:
\(y=\frac{k}{x}\)
where \(k\) is also called the constant of proportionality. If \(x\) increases, \(y\) decreases at the same rate. On the other hand, If \(x\) decreases, \(y\) increases at the same rate.
