It gives the perimeter of 14 mm and if it is 3 mm tall, times that by 2 to get 6 for the total of both side then subtract 6 from 14 and you get 8 and then divide that by 2 
Answer is 4 mm wide for the two sides
        
             
        
        
        
Answer:    50%
Step-by-step explanation:
 
        
                    
             
        
        
        
The answer to the equation is 8
        
                    
             
        
        
        
1/3 with a line over the answer ( 0.66666666666...)