Answer:
 
 represents the total perimeter of the table, and if x = 3 the lentgh of entire rubber bumper is 12 feet.
Step-by-step explanation:
Perimeter is defined as the sum of sides.
For a rectangle having dimension length 'L' and breadth 'B' Since, rectangle has two sides equal.
Perimeter of rectangle = 2 ( length + breadth )
Here, given rectangle has dimension 
Length = 
 and breadth = 
Thus, perimeter of rectangle = 
                                               
                                                
                                                 
Thus, perimeter of rectangle is 
   ........(1)
Perimeter of rectangle , when x = 3,
Put x= 3 in (1) ,

Thus, 
 represents the total perimeter of the table, and if x = 3 the lentgh of entire rubber bumper is 12 feet.