The piece connecting two incoincident points lying on one circle is called "chord", and the chord passing through the center of this circle has also one more name - "diameter". Such chord has length, greatest possible for this circle, which can be calculated in several ways, using basic definitions and ratios.
Instruction
1. The easiest way of determination of diameter (D) circle can be applied when the radius (R) of a circle is known. By definition the radius is the piece connecting the center of a circle to any point lying on a circle. From this follows that diameter is made by two pieces, length of each of which is equal to radius: D=2*R.
2. Use (D) ratio called Pi's number for calculation of diameter if length of perimeter (L) is known to you. In relation to a circle, it is accepted to call perimeter circle length, and Pi's number expresses a constant ratio between diameter and length of a circle - division of perimeter of a circle into its diameter is always equal in Euclidean geometry to Pi's number. Means, for finding of diameter you need to divide circle length into this constant: D=L/π.
3. From a root from result of division of the square at Pi's number and to double the received value: D=2 * √ (S/π).
4. If near a circle the rectangle is described and length of its party is known, then nothing will be required to calculate - the square can only be such rectangle, and length of its party will be equal to diameter of a circle.
5. In case of the rectangle entered in a circle length of diameter will coincide with length of its diagonal. For its location with the known width (H) and height (V) rectangle it is possible to use Pythagorean theorem as the triangle formed by diagonal, will be width and height rectangular. From the theorem follows that rectangle diagonal length, so and diameter of a circle, is equal to a square root from the sum of squares of width and height: D = √ (H²+V²).