The area of a circle is the total number of square units in the circle. If you have a circle in a 1cmx1cm drafting paper, you can simply count the number of boxes in your circle. That would be your area in square cm (cm2).
However, a more reliable, efficient and commonly used formula for calculating area of circles is:
Area = Pi x (Radius)2
The value of pi is always constant at 22/7 which is equivalent to 3.142.
The radius is the distance from the center of the circle to one peripheral line. It is always half the value of the diameter. A diameter is a line stretching from one point on a circles boundary to another and passing through the center of the circle. It is basically two radii joined together at the center in a straight line.
So, if you have a question where you are given the diameter and you need to know the radius, simply divide the value of diameter by 2:
Radius = Diameter/2
Or
Diameter = Radius x 2
(Note that while 2xradius=diameter, r2 is different. It is the radius multiplied with itself (radius x radius), while the diameter is radius + radius).
Hope circle area is no problem for you now!
However, a more reliable, efficient and commonly used formula for calculating area of circles is:
Area = Pi x (Radius)2
The value of pi is always constant at 22/7 which is equivalent to 3.142.
The radius is the distance from the center of the circle to one peripheral line. It is always half the value of the diameter. A diameter is a line stretching from one point on a circles boundary to another and passing through the center of the circle. It is basically two radii joined together at the center in a straight line.
So, if you have a question where you are given the diameter and you need to know the radius, simply divide the value of diameter by 2:
Radius = Diameter/2
Or
Diameter = Radius x 2
(Note that while 2xradius=diameter, r2 is different. It is the radius multiplied with itself (radius x radius), while the diameter is radius + radius).
Hope circle area is no problem for you now!
