A circle into three parts can be divided in two ways.
For one of them you will need a compass and a ruler, and for the second one you need a ruler and a protractor.
Which option is preferable - it's up to you.
You will need
- - compasses
- - ruler
- - protractor
Let a circle of radius R be given. It is necessary to divide it into three equal parts by means of a compass. Open the compass by the radius of the circle. You can use this ruler, but you can put the needle of the compass in the center of the circle, and move the leg to the circle that describes the circle. In any case, the ruler will come in handy later. Set the circular needle at an arbitrary point on the circle that describes the circle, and draw a small arc that crosses the outer contour of the circle. Then set the circular needle to the found intersection point and once again draw the arc with the same radius (equal to the radius of the circle). Repeat these steps until the next intersection point is the same as the first. You will get six points on a circle, located at regular intervals. It remains to choose three points through one and a ruler to connect them to the center of the circle, and you will get a divided circle in three.
To divide a circle into three parts usingProtractor, it is enough to remember that the complete revolution around its axis is 360 ° -. Then the angle corresponding to one third of the circle is 360 ° - / 3 = 120 ° -. Now set three times the angle of 120 ° - on the outside of the circle and connect the points obtained on the circle with the center.