Answer:
6.1
Step-by-step explanation:
hope it helps<3
 
        
             
        
        
        
We have been given that in triangle ABC angle A=45 angle B =40 and a=7. We are asked to find the equation that we can use to solve for 'f'.
We have two angles and opposite sides to these angles. 
We will use Law of Sines to solve our given problem. 
 , where a, b and c are opposite sides corresponding to angles A, B, and C respectively.
, where a, b and c are opposite sides corresponding to angles A, B, and C respectively.
The angle opposite to side b is 40 degrees and angle opposite to side a is 45 degrees.
Upon substituting these values in Law of Sines, we will get:

Therefore, our required equation would be  .
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D = 20 
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Answer:
140 minutes
Step-by-step explanation:
After 28 mins you've gone 4 miles, assuming this rate is constant and you dont slow down or speed up, in order to get to 20 miles you will have run 5x as much (20/4 = 5), thus 5x the amount of time (28x5). 
20/4 = 5
5x28 = 140 
 
        
                    
             
        
        
        
If B is the midpoint of AC, then AB=BC. It is also BC=AC-AB
AB = x + 6
AC = 5x - 6
BC = (5x - 6) - (x + 6)
We can kinda use distributive property, like this:
BC = 5x - 6 -x - 6
Combine like terms:
BC = 4x - 12
To verify, we can add AB and BC to see if their sum is equal to AC.
(x + 6) + (4x - 12) = 5x - 6
If we are correct, this equation will be true.
x + 6 + 4x - 12 = 5x - 6
Combine like terms:
6 + 5x - 12 = 5x - 6
5x - 6 = 5x - 6
It's correct!
BC = 4x - 12. Final Answer.
Let me know if you have any questions about this! :)