Hence If one side is a, the formula will be,S=7-a.
Area Covered By rectangle refers to product of two side of rectangle.
When we add all the sides of rectangle it gives us perimeter of rectangle that is
when we calculate circumference of rectangle it gives us perimeter.
Formula to calculate perimeter
=2(l+b)
Given Perimeter=14
14=2(l+b)
7=L+B
7-B=L
Given ne side is a
Then S=7-a
learn More about how to calculate Area of Rectangle
https://brainly.com/question/25292087
#SPJ2