Use the trig identity
2*sin(A)*cos(A) = sin(2*A)
to get
sin(A)*cos(A) = (1/2)*sin(2*A)
So to find the max of sin(A)*cos(A), we can find the max of (1/2)*sin(2*A)
It turns out that sin(x) maxes out at 1 where x can be any expression you want. In this case, x = 2*A. 
So (1/2)*sin(2*A) maxes out at (1/2)*1 = 1/2 = 0.5
The greatest value of sin(A)*cos(A) is 1/2 = 0.5
        
                    
             
        
        
        
The Greek mathematician who wrote the most definitive text on geometry, one that is still referred to today is Euclid. Euclid of Alexandria is also called "Father of Geometry". He was a great Greek mathematician. Euclidean geometry is still widely taught in schools and colleges. I hope the answer comes to your help.
        
             
        
        
        
To estimate, you can round 627 up to 630 and round 253 down to 250. 
650-250=380. 380 is your estimate.
The actual answer is 374.
 
        
                    
             
        
        
        
I believe that the answer is 1/5. I hope that this answer helps!<span />