Answer:
x ≈ 28.8°
Step-by-step explanation:
Using the sine ratio in the right triangle
sin x =  =
 =  =
 =  , then
 , then
x =  (
 ( ) ≈ 28.8° ( to the nearest tenth )
 ) ≈ 28.8° ( to the nearest tenth )
 
        
             
        
        
        
X + 3 because in math two negatives equal a positive
        
             
        
        
        
Average thickness of book = Total thickness/mo. of books
= 28 cm/ 10
= 2.8 cm
Thus, on average, each book has 2.8 cm thickness.
        
                    
             
        
        
        
9 Is in the hundred million place 
Hope I helped! ( Smiles )