You will need
  • calculator.
To find the area of the circle first, its radius lift to a square that is in the second degree. And then multiply the result by the number π (PI). If the problem is the radius given the diameter of the figure, can be split into 2. Now obtained by dividing the radius of the shapes use for the convenience of calculating the area of a circle.
To find the value of the square of the radius of a circle use a calculator. To start enter the value of radius of circle, then find a special button with the symbol x2. This symbol on the button shows that number to be raised to the second power. If you have any difficulty, multiply the radius of the circle on itself. To find the area of a circle, can use and diameter. The radius is ½ the diameter, and hence it can be represented as a fraction where the numerator is the value of the diameter, and in the denominator - 2. When computing the square of this fraction on a calculator, take the value of the diameter of the circle in the second degree, and then divide the resulting number by 4.
The value of the square of the radius of the circle , multiply by a factor of π (PI). To find the area of a circle, you can use a more exact or rounded value. To do this, enter the corresponding number (3,1415926535897932384626433832795 or 3.14). Often it is possible to use a special button marked with the symbol π (PI), as in many models of calculators.
The area of a circle is measure in square units. If the radius was given in centimeters (cm), area is expressed in square centimeters (cm2). When calculating radius from a diameter of the circle unit of measure does not change. For example, if the diameter were given in inches, then the radius will be measured in inches, and the desired area will be obtained in inches square. The problem is not always immediately specified radius. Sometimes initially given diameter of the circle. If you ignore this and use the diameter for calculations instead of the radius, the inevitable errors in calculations. To find the radius, the size of the diameter divide by 2.