Question

Which ordered pair would form a proportional relationship with the point graphed below? (60,-20)

Answer 1

Given:

The graphed point is (60,-20).

To find:

The ordered pair that would form a proportional relationship with the given point.

Solution:

If y is proportional to x, then

$y\propto x$

$y=kx$

$\dfrac{y}{x}=k$

Where, k is the constant of proportionality.

For the given point,

$k=\dfrac{-20}{60}$

$k=\dfrac{-1}{3}$

For option (A),

$k=\dfrac{30}{-10}$

$k=-3\neq \dfrac{-1}{3}$

For option (B),

$k=\dfrac{-15}{30}$

$k=-\dfrac{1}{2}\neq \dfrac{-1}{3}$

For option (C),

$k=\dfrac{10}{-30}$

$k=\dfrac{-1}{3}$.

The point (-30,10) gives the same value of the constant of proportionality. So, the point (-30,10) forms a proportional relationship with the given point.

Therefore, the correct option is C.