Answer-
The value of x can be anything between 0 to 15
Solution-
Perimeter of a geometrical figure is the sum of lengths of all its sides.
So, the value of the perimeter of the given pentagon would be,

As given in the question that, the perimeter is less than or equal to 51 meters.
So,


As the side length can not be negative, so x must be positive, i.e
