Number 1 is Rio Grande and number 2 is St. Lawrence River 
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
-17
Step-by-step explanation:
-6-11=-17
 
        
             
        
        
        
See the picture attached to better understand the problem
we know that
in the right triangle ABC
cos A=AC/AB
cos A=1/3
so
1/3=AC/AB----->AB=3*AC-----> square----> AB²=9*AC²---->  equation 1
applying the Pythagoras Theorem
BC²+AC²=AB²-----> 2²+AC²=AB²---> 4+AC²=AB²----> equation 2
substitute equation 1 in equation 2
4+AC²=9*AC²----> 8*AC²=4----> AC²=1/2----> AC=√2/2
so
AB²=9*AC²----> AB²=9*(√2/2)²----> AB=(3√2)/2
the answer isthe hypotenuse is (3√2)/2
 
        
        
        
Answer:
I think it is 20cm
Step-by-step explanation:
 divide 80 by 4 =20 cm