Suppose that the length of a rectangle is 3 inches longer than the width and that the perimeter of the rectangle is 78.

Set up an equation involving only W, the width of the rectangle.

For:

Assume all values are in inches.
L=length of rectangle
W=width of rectangle
P=perimeter of rectangle
P=L + W + L + W
The problem states:
P=78
L=W + 3
Substitute the above values into the perimeter equation.

To set up an equation involving only the width of the rectangle, let's first assign a variable to represent the width. Let's use W to denote the width.

According to the problem, the length of the rectangle is 3 inches longer than the width. So, the length can be expressed as W + 3.

Now, let's recall the formula for the perimeter of a rectangle: Perimeter = 2(Length + Width)

We are given that the perimeter of the rectangle is 78. Substituting the expressions for length and width into the formula, we get:

78 = 2(W + 3 + W)

Simplifying the equation, we have:

78 = 2(2W + 3)

Now, we can solve this equation to find the value of W, which represents the width of the rectangle.