The length of the rectangular section is 30m, and the width is 20m. How long is the fence that encloses this area?

To answer the question of the problem, you need to know the perimeter of a rectangular area. The perimeter of a rectangle is equal to the sum of all its four sides, and also the perimeter of a rectangle is equal to the sum of its length and width multiplied by two.
The first way to solve the problem.
1. How long is the fence that encloses the site?
30 + 20 + 30 + 20 = 100 meters.
The second way to solve the problem.
2.  Determine the length of the fence that encloses the site.
(30 + 20) * 2 = 100 meters.
Answer: The length of the fence enclosing the site is 100 meters.