Step by step
The question
Question: find the area when the pressure is 12 N/cm² and the force is 96 N.
1 Write the rule
The rule: pressure is the force divided by the area.
Pressure tells us how much force pushes on 1 cm².
So its unit is N per cm².
2 Put the numbers in
The pressure is 12.
The force is 96.
The area is what we want: we call it x.
3 Move x to the top
x is at the bottom.
Times x moves it up.
We do it on both sides, so they stay equal.
x divided by x is 1.
So just 96 is left on the right.
Now we have 12x = 96.
4 Remove the 12
12x means 12 times x.
We want just x.
To remove times 12, we divide by 12.
We do it on both sides.
Why both sides?
The = sign means both sides are the same amount.
If we change only one side, they are not the same any more.
12 divided by 12 is 1.
So just x is left.
96 divided by 12 is 8.
So x = 8!
5 Check
Let's check: put 8 in place of x.
We get 96, the same as the right side.
So x = 8 is right!
So the area is 8 cm².
Let's look back.
First: write the rule.
Then: put the numbers in.
Then: move x to the top.
Then: remove the 12.
Last: check.