Inverse Variation: Solving Problem Formula

[Coder74]

What is the formula to solving a problem like this?
Thanks in advance!

View attachment 6458

 

[MarkFL]

The statement that pressure $P$ varies inversely with area $A$ may be written mathematically as:

$$P=\frac{k}{A}\tag{1}$$

Where $k$ is called the constant of proportionality. We may determine $k$ from the information provided, namely that we know the pressure for a given area. We are given:

$$(A,P)=(40,4)$$

Substitute that ordered pair into equation (1), and then solve for $k$...what do you get? You should in fact find that the value of $k$ makes perfect sense here. ;)