Applet+Geometry+Concept

media type="custom" key="10288363" Start with the simple image of 2 circles with the same radius. (uncheck all the options). Build up the image slowly so that the more complex image makes sense to you. The triangle is an equilateral because the three sides are the same (the circles share the same length radius.) So the angles must be 60 degrees, and the vertical line must be at 90 degrees because of symmetry. Then 6 equilateral triangles form a regular hexagon.

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