Answer:
$7 
Davon charges $7 per hour of rental
 
        
             
        
        
        
Given:
In triangle OPQ, o = 700 cm, p = 840 cm and q=620 cm. 
To find:
The measure of angle P.
Solution:
According to the Law of Cosines:

Using Law of Cosines in triangle OPQ, we get




On further simplification, we get




Therefore, the measure of angle P is 79 degrees.
 
        
                    
             
        
        
        
Part A - 226.865 or 226.87
Part B - 120
Part C - 106.865