Question

Use the table below. Do x and y have a proportional relationship? Explain.x 2, 3, 5, 8y 5, 7.5, 12.5, 18

Answer 1

ANSWER

Not a proportional relationship

EXPLANATION

For this to be a proportional relationship the ratio y:x for each pair of the table must be constant:

For the first pair:

$\frac{5}{2}$

Second pair:

$\frac{7.5}{3}=\frac{\frac{15}{2}}{3}=\frac{15}{3\cdot2}=\frac{5}{2}$

Third pair:

$\frac{12.5}{5}=\frac{\frac{25}{2}}{5}=\frac{25}{2\cdot5}=\frac{5}{2}$

Until now the ratio is constant, but for the fourth pair:

$\frac{18}{8}=\frac{9}{4}$

The ratio is different. Therefore, the relation between x and y in the table is not proportional.