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GeoGebraGeoGebra Classroom

Department of the Exterior Angles

Relationships Drag the red points to change / move the polygon. Do the angles change? Drag the black slider to change the number of sides that the polygon has. ▪ Notice how the two angles change. ▪ What pattern links the sizes of the angles and the value of ?
Math Data On the following polygon applets, move any of the LARGE POINTS anywhere you'd like! See what happens when you move the white points, the black point on the slider, and the yellow point. When you zoom in or out, be sure you can still see all of those points. If you feel like you are having trouble with what to do, scroll to the bottom of the page to watch the quick demo video.

TRIANGLE: Applet

TRIANGLE: Question

Suppose the blue angle measures 120 degrees and the pink angle measures 140 degrees. What would the measure of the purple angle be?

Note: For the polygons that follow (quadrilateral, pentagon, hexagon), these applets will work best if the polygon is kept CONVEX. If you don't remember what the term, convex, means, click here for a refresher.

QUADRILATERAL: Applet

QUADRILATERAL: Question

Suppose the blue angle measures 120 degrees and the pink angle measures 140 degrees and the green angle measures 80 degrees. What would the measure of the purple angle be?

PENTAGON: Applet

HEXAGON: Applet

Quick (Silent) Demo