Answer:
40 inches.
Explanation:
If you want to measure how much fence you need to enclose a rectangle, you have to add up the lengths of all its sides. That's called the perimeter. The easiest way to find it is to use this handy-dandy formula:
Perimeter = 2 (length + width) units
where length and width are how long the rectangle's sides are.
For example, let's say you have a rectangle that is 12 inches long and 8 inches wide. To find its perimeter, you just plug in those numbers into the formula:
Perimeter = 2 (12 + 8) inches
Perimeter = 2 (20) inches
Perimeter = 40 inches
Ta-da! The perimeter of the rectangle is 40 inches.