1.1 与一定点等距的动点的轨迹

Locus of a moving point and a fixed point

2.2 作等边三角形

The applet below dynamically illustrates how an equilateral triangle can be constructed via compass and straightedge. [br][br][b][color=#0000ff]Why is this method of construction valid? [/color][/b]

3.1 作中垂线与中点

Check the steps to construct the perpendicular bisector of a line segment.[br]You can also see how changes in the span of the compass or in the position of the points affect the construction.

4.1 作一角等于已知角

Given an angle at a point A, and given a ray emanating from a point B, construct an angle at В equal to the angle at A (par = 4).[br][br]3 circles + 1 line = 4 steps.

5.1 作已知三边的三角形SSS

Konstruisati trougao ako su date dužine sve tri stranice.

6.1 作经过直线外一点的平形线

7.1 作三角形的外接圆

Konstruisati opisanu kružnicu oko datog trougla ABC.
Centar opisane kružnice je u preseku simetrala stranica trougla. Zašto se simetrale stranica seku u jednoj tački?

8.3 作正五边形

Move the control (red cross) from left to right to see how a regular pentagon inscribed inside a circle can be constructed
Try to explain why this method work.

Information