10 is the missing number.
        
             
        
        
        
Answer:
170	square feet
Step-by-step explanation:
 
        
             
        
        
        
Answer:
Yes
Step-by-step explanation:
1) Cos 300 = Cos (360 - 60) = Cos 60    {Cos 360 - theta = Cos theta}
                                               = 1/2
Sin 300 = Sin (360 - 60) = -Sin 60 = 
 3) 3π/4 = 3*180/4 = 135
Cos 135 = Cos (90 + 45) = -Cos 45 = 
Sin 135 = Sin (90 + 45) = Sin 45 = 
 
        
             
        
        
        
One board is 31.5 inches long. all the boards together is 157.5 inches long