In math, 3.14 (Pi) multiplied by the radius squared is the mathematical equation used to calculate the area of a circle.

The area of a circle is calculated by first measuring the radius (half of the distance from one side of the circle to the other - the diameter) and then multiplying it by itself, i.e. Squaring it. For example, if you have a circle that has a 30 centimeter diameter, it will have a 15 centimeter radius. You will then have to calculate 15 time 15 in order to get the number 225. This number will now need to be multiplied by Pi. If you are using a calculator with a Pi function button, this will give you the most accurate result. For an approximation it is possible to round Pi to two decimal places, 3.14. Following the example above, 225 can be multiplied by 3.14 to give the answer of 706.5 centimeters square.

Once you have calculated the area of a circle it is then possible to carry out more complicated equations such as calculating the area of a sector. To do this you will need to know the area of the circle and the angle of the sector that you want to calculate the area for. Simplify the fraction of the sector angle over 360 degrees to its lowest form. For example, if the angle of the sector is 120 degrees the fraction would be 120/360. In its simplest form this is 1/3. Now take the area of the circle, with the same example this would be 706.5, and divide it by 3, as this will give 1/3 of the circle's area. In this example the answer is 235.5 centimeters square. Alternatively a sector that has an angle of 90 degrees would form the fraction 90/360, simplified to 1/12. 706.5 divided by 12 gives a sector area of 58.88 centimeters square.

The area of a circle is calculated by first measuring the radius (half of the distance from one side of the circle to the other - the diameter) and then multiplying it by itself, i.e. Squaring it. For example, if you have a circle that has a 30 centimeter diameter, it will have a 15 centimeter radius. You will then have to calculate 15 time 15 in order to get the number 225. This number will now need to be multiplied by Pi. If you are using a calculator with a Pi function button, this will give you the most accurate result. For an approximation it is possible to round Pi to two decimal places, 3.14. Following the example above, 225 can be multiplied by 3.14 to give the answer of 706.5 centimeters square.

Once you have calculated the area of a circle it is then possible to carry out more complicated equations such as calculating the area of a sector. To do this you will need to know the area of the circle and the angle of the sector that you want to calculate the area for. Simplify the fraction of the sector angle over 360 degrees to its lowest form. For example, if the angle of the sector is 120 degrees the fraction would be 120/360. In its simplest form this is 1/3. Now take the area of the circle, with the same example this would be 706.5, and divide it by 3, as this will give 1/3 of the circle's area. In this example the answer is 235.5 centimeters square. Alternatively a sector that has an angle of 90 degrees would form the fraction 90/360, simplified to 1/12. 706.5 divided by 12 gives a sector area of 58.88 centimeters square.