The circle is a flat geometrical figure which all points are on removal, identical and other than zero, from the chosen point which is called the center of a circle. The straight line which is connecting any two points of a circle and passing through the center call it diameter. Total length of all borders of a two-dimensional figure which is usually called perimeter at a circle more often is designated as "the circle length". Knowing length of a circle it is possible to calculate and its diameter.
Instruction
1. Use for finding of diameter one of the main properties of a circle which is that the ratio of length of its perimeter to diameter is identical to all circles. Of course, such constancy remained noted by mathematicians, and this proportion received own name for a long time - it is Pi's number (π - the first letter of the Greek words "circle" and "perimeter"). Numerical expression of this constant is defined by length of a circle at which diameter is equal to unit.
2. You divide the known length of a circle into Pi's number to calculate its diameter. As this number is "irrational", has no final value - it is a recurring decimal. Round Pi's number according to the result accuracy which you need to receive.
3. Use any calculator to calculate diameter length if it is impossible to make it in mind. For example, it is possible to use that which is built in the search engine Nigma or Google - he understands the mathematical operations entered in "human" language. For example, if the known length of a circle is four meters, then for finding of diameter it is possible to ask search engine "properly": "to divide 4 meters on p". But if you enter into the field of a search query, for example, "4/p", then the searcher will understand also such problem statement. Anyway the answer will be "1.27323954 meters".
4. Use the program Windows calculator if interfaces with ordinary buttons are more habitual to you. Not to look for the reference to its start in deep levels of the main menu of a system, press a combination of the keys WIN + R, enter the calc team and press the Enter key. The interface of this program very slightly differs from ordinary calculators therefore operation of division of length of a circle into Pi's number will hardly cause any difficulties.