When carrying out creation of various geometrical figures sometimes it is required to define their characteristics: length, width, height and so on. If it is about a circle or a circle, then often it is necessary to determine their diameter. Diameter represents a straight line piece which connects two the most remote from each other the points located on a circle.
It is required to you
- - measuring ruler;
- - compasses;
- - calculator.
Instruction
1. In the simplest case determine diameter by formula D = 2R where R is circle radius with the center in a point of the Lake. Such formula is convenient if you draw a circle with in advance stipulated radius. For example, if at creation of a figure you establish solution of legs of compasses of equal 50 mm, then diameter of the circle received as a result will be equal to the doubled radius, that is 100 mm.
2. If length of the circle making external border of a circle is known to you, then use a formula for determination of diameter: D = L / p, gdel – circle length; p – number "пи", equal about 3.14. For example, if length of a circle is equal to 180 mm, then diameter will equal approximately: D = 180 / 3.14 = 57.3 mm.
3. If you have previously drawn circle with unknown the radius, diameter and length of a circle, then for approximate measurement of diameter use compasses and a measuring ruler with divisions. The complexity is in finding on a circle two points, the most far remote from each other, that is such which will be located on diameter.
4. By means of a ruler draw a straight line that it crossed a circle in any place. Note points of intersection of the line and a circle as And yes V. Teper Establish compasses solution so that it was more than a half of a piece of AV.
5. Establish a compasses needle in a point And yes carry out the arch crossing a piece of AV or even a circle. Now, without changing compasses solution, establish it in a point In and do the same. As a result you receive points of intersection of two circles on both sides from AV piece. Connect them on a ruler a straight line that it crossed a circle in points of C and D. CD piece will also be required diameter.
6. Now measure diameter by means of a measuring ruler, having put it to points of C and D. The second way of determination of diameter: to put compasses legs in the beginning to points of C and D, and then to transfer compasses solution to a measuring scale of a ruler.