INSPECTING INTERIOR ANGLES
Measure the Angles
For each polygon applet below, follow the steps to create the polygon and find the interior angle measures. Draw a sketch of your polygon, identify the number of sides, and record the sum of the angle measures in the table of your handout.
Triangle
1. Use the Polygon 
Tool to create a triangle (3 sides).
To do this, click to place each vertex, then click on the first vertex to close the shape.
2. Click on the Angle 
Tool, then click anywhere inside of the shape.
Tool to create a triangle (3 sides).
To do this, click to place each vertex, then click on the first vertex to close the shape.
2. Click on the Angle Tool, then click anywhere inside of the shape.
Quadrilateral
1. Use the Polygon Tool to create a quadrilateral (4 sides).
2. Click on the Angle Tool, then click anywhere inside of the shape.
Tool to create a quadrilateral (4 sides).
2. Click on the Angle Tool, then click anywhere inside of the shape.
Pentagon
1. Use the Polygon Tool to create a pentagon (5 sides).
2. Click on the Angle Tool, then click anywhere inside of the shape.
Tool to create a pentagon (5 sides).
2. Click on the Angle Tool, then click anywhere inside of the shape.Hexagon
1. Use the Polygon Tool to create a hexagon (6 sides).
2. Click on the Angle Tool, then click anywhere inside of the shape.
Tool to create a hexagon (6 sides).
2. Click on the Angle Tool, then click anywhere inside of the shape.Heptagon
1. Use the Polygon Tool to create a heptagon (7 sides).
2. Click on the Angle Tool, then click anywhere inside of the shape.
Tool to create a heptagon (7 sides).
2. Click on the Angle Tool, then click anywhere inside of the shape.Octagon
1. Use the Polygon Tool to create an octagon (8 sides).
2. Click on the Angle Tool, then click anywhere inside of the shape.
Tool to create an octagon (8 sides).
2. Click on the Angle Tool, then click anywhere inside of the shape.Nonagon
1. Use the Polygon Tool to create a nonagon (9 sides).
2. Click on the Angle Tool, then click anywhere inside of the shape.
Tool to create a nonagon (9 sides).
2. Click on the Angle Tool, then click anywhere inside of the shape.Decagon
1. Use the Polygon Tool to create a decagon (10 sides).
2. Click on the Angle Tool, then click anywhere inside of the shape.
Tool to create a decagon (10 sides).
2. Click on the Angle Tool, then click anywhere inside of the shape.Find the Pattern
After completing the table on your handout, look for patterns in the data you have collected. Use this information to predict the sum of the interior angles of a polygon with 13 sides.
Think about the kind of reasoning you used to come to this conclusion, and answer the questions on your handout.
When you finish, go to the Use the Facts GeoGebra activity.