Answer:
In a supplementary angle the angle is 360°
in a complementary angle the angle is 180° 
 
        
             
        
        
        
Sometimes it helps to draw it out...
     (17)
C_______M_________Q
|___________________|
             21
therefore, CM + MQ = CQ
17 + MQ = 21
MQ = 21 - 17
MQ = 4 <===
        
                    
             
        
        
        
I think it’s $3.55 
I think this because if u subtract 2.45- 45% = 1.10 sooo u will have to add $1.10 to 2.25 and that will add up the 45% that Walmart is paying with the original price.