Question

What is the constant of proportionality in the equation 9y = 45x?

Answer 1

Divide by the coefficient of y.
  y = (45/9)x
  y = 5x

The constant of proportionality is 5.

Answer 2

We have been given an equation $9y=45x$ and we are asked to find the constant of proportionality of this equation.

In order to find constant of proportionality we will use proportionality constant formula $y=kx$ , where k is proportionality constant.

Now let us try to write our given equation in this form,

$9y=45x$

Now let us divide both sides of our equation by 9

$\frac{9y}{9}=\frac{45x}{9}$

After dividing both sides of our equation by 9 we will get

$y=5x$

Upon comparing our equation with  $y=kx$ we get proportionality constant as 5.