00:01
Okay, so in this problem, we're given that the perimeter is equal to 280 centimeters.
00:08
And we also know that the width is, well, we can just go ahead and write the equation for this.
00:18
The width is 20 centimeters less than the length.
00:23
So that means we can do the length minus 20 centimeters.
00:28
Now, whenever you're giving a problem like this and you're giving words like perimeter or area, the first thing you want to do is just write down what is the formula for the perimeter of that shape.
00:38
Since this shape is a rectangle, we can do 2 times length plus 2 times width equals the perimeter, which is 280.
00:52
And then we also know that the width is 20 centimeters less than the length.
00:59
So we can use substitution and we're going to put l minus 20 in for w.
01:06
So we're going to have 2l plus 2 times l minus 20 and that's going to equal 280...