In drawing often it is required to build regular polygons. So, for example, the correct octagons are used on boards of road signs.
It is required to you
- - compasses
- - ruler
- - pencil
Instruction
1. Let the piece equal to length of the party of a required octagon be set. It is required to construct correct octagon. The first step construct an isosceles triangle on the set piece, using a piece as the basis. For this purpose at first construct a square with the party equal to a piece, carry out in it diagonals. Now construct bisectors of corners at diagonals (in the drawing of a bisector are specified by blue), on crossing of bisectors the top of an isosceles triangle which parties are equal to the radius of the circle described around the correct octagon is formed.
2. Construct a circle with the center in triangle top. Radius of a circle is equal to the party of a triangle. Now part compasses on the distance equal to size of the set piece. Lay off this distance for circles, beginning from any end of a piece. Connect all received points in an octagon.
3. If the circle in which the octagon has to be entered is set, then constructions will be even simpler. Build two center lines perpendicular each other passing through the center of a circle. On crossing axial and circles will turn out four tops of future octagon. It was necessary to divide distance between these points on a circle arch in half to receive four more tops.