The circle will be considered entered in a polygon only if all parties of this polygon without exception concern this circle. It is very simple to find length of an inscribed circle.
Instruction
1. To learn circle length, it is necessary to possess to data on its radius or diameter. The piece which connects with each other the center of this circle to any of the points belonging to a circle is considered the radius of a circle. Diameter of a circle is the piece which connects circle points opposite each other, thus surely passing through the center of a circle. From definitions it becomes clear that the radius of a circle is twice less than its diameter. The center of a circle is the point which is equally removed from each of points on a circle. Formulas by means of which there is circle length look so: L = π*D, where D - diameter of a circle; L = 2*π*R where R is circle radius. Example: Diameter of a circle is 20 cm, it is required to find its length. This problem is solved with application of the very first formula: L = 3.14*20 = 62.8 smotvt: Length of a circle with a diameter of 20 cm is 62.8 cm
2. Having decided on how there is circle length, it is necessary to find out how to find the radius or diameter of the circle entered in a polygon. If in a polygon its area is known to S and also it poluperimetr for P, then it is possible to find the radius of an inscribed circle by means of such formula: R = S/p
3. For the sake of clearness of the data given above, it is possible to review an example: The circle is entered in a quadrangle. The area of this quadrangle of 64 cm², poluperimetr it it is equal to 8 cm, asks to find length of the circle entered in this polygon. For the solution of this task it is necessary to perform several operations. At first it is necessary to find the radius of this circle: R = 64/8 = 8 smteper, knowing its radius, it is possible to calculate, actually, and length of this circle: L = 2*8*3.14 = 50.24 smotvt: length of the circle entered in a polygon is 50.24 cm