Constant of proportionality through (4, 12)

Step by step

The question

Question: find the constant of proportionality for the point (4, 12).

Proportional means: y divided by x is always the same number.

We call that number k.

Then y = k times x.

1 Divide y by x

x is 4 and y is 12.

So k is 12/4, which is 3.

2 Write the equation

y = k x, with k = 3.

So the equation is y = 3x.

3 Check

Let's check: k times x should give each y.

3 times 4 is 12.

So the answer is right!

Let's look back.

First: divide y by x.

Then: write the equation.

Last: check.