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GeoGebraClasse GeoGebra

Interior & Exterior Angles

Investigating Interior and Exterior Angles

1. Determine the sum of the interior angles of the triangle and quadrilateral below.

  • Start by measuring the interior angles of each polygon. To do this quickly, select the Angle tool Toolbar Image, and click anywhere on the interior (inside) of the shape.
  • Add up the sum of all the interior angles of each shape and record this on your paper. Does the sum for each shape change if you drag the shape around, or does it always stay the same?
*Hint. Use the Move tool Toolbar Image to drag the labels of the angle measures around so that they are easier to read.

2. Determine the sum of the interior angles of the pentagon and hexagon below.

  • Once again, measure all interior angles in each polygon.
  • Add up the sum of all the interior angles of each shape and record this on your paper. Does the sum for each shape change if you drag the shape around, or does it always stay the same?

3. Determine the sum of the exterior angles of the triangle below.

Colored points have been included to help you measure angles.
  • Select the Angle tool Toolbar Image.To measure angle x, select any green point, followed by the black point adjacent to angle x, followed by the other green point. *Each black point is a vertex of the triangle.
  • Repeat the above steps for angle y and angle z

4. Determine the sum of the exterior angles of the quadrilateral below.

*A button to show/hide the exterior angles is given to save time

5. Determine the sum of the exterior angles of the pentagon below.