To calculate the area of a circle, use the equation a=pir^2 or area=3.14*radius squared
Insert the known values. We need to find the radius of the circle. Since the radius is half of the diameter, divide the diameter by 2 to get the radius.
The diameter of this circle is 20. The radius is half the diameter so the radius is 10.
You substitute 10 for r in the formula to get A = π(10)^2. 10 to the second power is 10 times 10 which is 100 so you get A= π(100). When you multiply π by 100, you get 314.15 which rounded to the nearest tenth is 314.5.
The area of the circle is 314.5 squared centimeters.
