The constant of proportionality is the ratio between two directly proportional quantities. Two quantities are directly proportional when they increase and decrease at the same rate. The constant of proportionality k is given by,
[tex]k=\frac{y}{x}[/tex]
So here, we have,
[tex]k=\frac{160}{25}=\frac{320}{50}=\frac{480}{75}=\frac{640}{100}=6.4[/tex]
Thus, the constant of proportionality is 6.4.
