The differences in the areas of circles in square centimeters is 49.455
Formula for area of circle
A is the area of circle
r is the radius of circle
and π = 3.14
What is radius of a circle ?
Radius of circle is the distance from the center of the circle to any point on it's circumference. It is calculated as :
According to the given question
Diameter of one circle is 12cm and diameter of another circle 9cm.
Area of circle with diameter 12 cm = = = 113.04 square cm
Area of circle with diameter 9 cm = square cm
The difference between the areas of two circles = (113.04 -63.585) square centimeter = 49.455 square centimeter.
Learn more about the area of circle here:
Area of circle= π(d/2)²
For 1st Circle, A1= 36π
For 2nd Circle, A2= 81π/4
A1-A2 = 63π/4
π = 22/7