Answer:
3 cm 
Step-by-step explanation:
 (Given) (Given)
 (Given) (Given)
- Formula for  is given as: is given as:
- Length of radius can not negative
Hope it helps you in your learning process.
 
        
                    
             
        
        
        
Answer: 1.83
Step-by-step explanation:
Hope this helps!
 
        
             
        
        
        
Answer: -n-4
Step-by-step explanation:
Distribute the - to n and 4