Answer:
17: 6:48
18: 9:45
19: 85 minutes or 1 hour and 25 minutes
20: 165 minutes or 2 hours and 45 minutes 
Step-by-step explanation:
 
        
                    
             
        
        
        
B is the correct answer for your question I do believe, I hope that helped you. If not I am sorry, I tried to answer fast for you.
        
             
        
        
        
Answer:
The answr is 102 degrees. Here's why
Step-by-step explanation:
The square means the angle is 90 degrees. Therefore, for the big triangle, we already know 2 of the degrees, 50 and 90. A triangle's degrees add up to 180. 50+90=140. 180-140=40. This means the top angle is 40. Now finding X is easy, because we already know the other 2 points in the triangle, which are 38 and 40. Add those up, you get 78. 180-78=102, your answer. The triangle is 102 degrees. 
 
        
                    
             
        
        
        
It doesn't
remember that
(x/g) times (y/z)=(x time y)/(g times z) so 
2pi/4=(2 times pi)/(4 times 1) so 
2pi/4=2/4 times pi/1=1/2 times pi/1=pi/2
        
             
        
        
        
We need a pic to see what is the shape lol