Drag the vertices to make a convex heptagon. Enter the sizes of the angles in the boxes. Determine the angle sum.
Repeat this procedure using different heptagons. Make a conjecture about the sum of the angles. Can you provide a counter-example to your conjecture?
Click the blue reset button in the top right corner to reset the applet.
Brothen, 31 August 2013, Created with GeoGebra