The length of a rectangle is one less than 4 times the
width. If the perimeter is 28 feet, find the dimensions of the rectangle.
The problem tells us a lot about the length of the rectangle, but it doesn't say much about the width. Since we don't know much about the width, we'll call the width x. And if the length is one less than 4 times the width, we can then call the length 4x1. We'll add these variable definitions for the length and the width to our picture:
According to the problem, the perimeter of this rectangle is 28 feet. Since perimeter means the distance around an object, we can add the lengths of all four sides of the rectangle to find its perimeter. Adding the sides gives us the equation:
(x) + (4x  1) + (x) + (4x  1) = 28
10x  2 = 28
10x = 30
x = 3
So the width of the rectangle is 3 feet.
Before we leave this problem, let's think about our answer
one more time to see if it is consistent with the words of the problem:


The length of a rectangle is one less than 4 times the width.  Our length is 11, and our width is 3. Is 11 equal to one less than the quantity (4 times 3)? Yes! 
The perimeter is 28 feet  Our length is 11 and our width is 3. Adding all four sides would give us 11+3+11+3. Does this give us a perimeter of 28? Yes! 
We're done. Our answer is correct!