This chapter shows you how you can use KGeo for your lessons.

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Construct the circle of Thales

Please, do the following:

Construct three points at (-2;0), (0;0) and (2;0)

Construct a circle around the point in the middle with the radius 2.

Construct a point on this circle.

Draw a triangle through this point an the one on the left and on the right.

Measure the top angle.

If you move the point on the upper half of the circle, the angle will remain 90 deg.