Answer:
you are so smart :)))
Step-by-step explanation:
 
        
             
        
        
        
The one that you have marked in the picture is right because you are taking away two hours and dividing 400 by s
        
             
        
        
        
Answer:
100°
Step-by-step explanation:
 
        
                    
             
        
        
        
Use SOHCAHTOA.  Since we are looking for the hypotenuse, you must use sine or cosine.  Since, we are given the adjacent side, use cosine.
cosx=a/h
cos45=8/h
√2/2=8/h
<em>*Cross multiply*</em>
h√2=16
<em>*Divide both sides by √2*</em>
h=16/√2
<em>*Multiply by √2/√2*</em>
h=(16√2)/2
<em>*Simplify the fraction*</em>
h=8√2
Hope this helps!!