I hope you understand your answer is this
 
        
        
        
Answer:
Step-by-step explanation:
Since area of a circle is pi.r^2
We know that diameter is 20
Radius is half of diameter 
So it becomes 
Pi.(d/2)^2
So pi.(40/4) is the area of this circle.
Or 40pi/4
 
        
                    
             
        
        
        
Answer:
The polynomial is a quadratic binomial
Step-by-step explanation:
we have

Classify the polynomial
<u>By the number of terms</u>
we know that
A polynomial with two terms is a binomial
<u>By the Degree of a Polynomial</u>
we know that
The degree of a polynomial is calculated by finding the largest exponent in the polynomial
In the given problem the largest exponent is 
so
Is a quadratic equation
therefore
The polynomial is a quadratic binomial
 
        
                    
             
        
        
        
Answer:
The equation 2d + 18 = 24 can help find the number of days Jerry has been doing sit-ups.
Step-by-step explanation:
During the first day, Jerry did 18 sit-ups, and he proceeded to do 2 more sit-ups each following day, so the expression to represent this situation is 2d + 18. Because he did 24 sit-ups today, to find the number of days he did sit-ups, the equation to solve is 2d + 18 = 24.