Step by step
The question
Question: find the area when the pressure is 25 N/m² and the force is 150 N.
1 Write the rule
The rule: pressure is the force divided by the area.
Pressure tells us how much force pushes on 1 m².
So its unit is N per m².
2 Put the numbers in
The pressure is 25.
The force is 150.
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 150 is left on the right.
Now we have 25x = 150.
4 Remove the 25
25x means 25 times x.
We want just x.
To remove times 25, we divide by 25.
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.
25 divided by 25 is 1.
So just x is left.
150 divided by 25 is 6.
So x = 6!
5 Check
Let's check: put 6 in place of x.
We get 150, the same as the right side.
So x = 6 is right!
So the area is 6 m².
Let's look back.
First: write the rule.
Then: put the numbers in.
Then: move x to the top.
Then: remove the 25.
Last: check.