Since one side is 40°, you subtract that from 180.
180° - 40°= 140°.
So therefore your missing side lengths are 140, 40, and 140.
hopefully this helps
        
                    
             
        
        
        
Answer:
SSS postulate because three sides of a triangle are are congruent
 
        
                    
             
        
        
        
You know that BC is congruent to x so you need to solve for x using the ratio:

So then we need to find BC.
We know:


Therefore BC =8
Then:

