9.42 is the circumference, for future refernce its just pi times diameter :)
Answer:
Area of the circle = 
Step-by-step explanation:
Radius of the circle= 
Area of the circle= 
As,

Area of the circle is:

The Area of the circle is : 
The area of a circle if the diameter is 80 is
A=5026.55
The standard form would be 210,640,050.