00:01
A rectangle has an area of 36 square inches and the length is one third as long as the width.
00:09
You want to find the perimeter, length and width of the rectangle.
00:15
So situation, let's say we have a rectangle like this, and then let's say this is the width, this is the length, or rather the other way around, length, width, better.
00:33
And we know the area of the rectangle, let's call it a, is calculated as w times l.
00:42
And that value is 36 square inches.
00:50
And the other information we have is the length, l, is one third of the width.
00:58
That is, l is one third times w.
01:02
So we can put this expression of l into the equation given the area.
01:09
We can say then that width times l, that is times one third times w, is 36 inches square.
01:24
So here we have one third times w square is 36 square inches.
01:36
And that means that w square is 108 square inches.
01:52
Now 108 can be left rather as 3 times 36, more convenient, instead of, that is we can get rid of this expression, but just the same.
02:09
So w square is 3 times 36 square inches.
02:16
Now we take square root to get w, and we remember w is a measure, so it's a positive number, so we keep only the positive solution from this equation...