An exponential model can be described by the function 

where: a is the initial population or the starting number, b is the base and x is the number of periods elapsed.
When the base of an exponential model is greater than 1 it is called a growth factor, but when it is less than 1 it is called a decay factor.
Given the exponential model 

n is the final output of the exponential model, 20.5 is the starting number, 0.6394 is the base and t is the number of periods/time elapsed.
Here, the base is 0.6394 which is less than 1, hence a decay factor.
Therefore, <span>the
base, b, of the exponential model is 0.6394; It is a
decay factor.</span>
 
        
        
        
Answer:
The answer is C
Step-by-step explanation:
I got it correct :)
 
        
                    
             
        
        
        
Your I. Your own sis 3662
        
             
        
        
        
B. supplementary
The measures of supplementary angles add up to 180 degrees.