T103 – Sum of Interior Angles of Convex Polygons

Using The Geometer’s Sketchpad

 

  1. Go to the Math Lab (LF 101) and open The Geometer’s Sketchpad program (Math Apps folder)

 

  1. Construct a convex polygon with 5 sides.

Click on the                  symbol and then draw the sides by holding the mouse button in  the sketch and dragging to the desired location

 

  1. Have the computer measure each angle:
    1. Click on the            symbol

 

    1. Hold down the Shift key
    2. Click on 3 consecutive points that will form an angle
    3. Go to the Display menu at the top of the page
    4. Then select “Show Labels”
    5. Go to the Measure menu at the top of the page
    6. Then select “Angle”
    7. Click in the middle of the polygon to clear all the highlighted points
    8. Go back to step b, to measure all 5 angles

 

  1. Repeat Steps 2 and 3 for convex polygons with 6, 7, 8, and 9 sides.  You can draw all the polygons in the same window and print all together or do each one separately and print separately.

 

  1. Complete the table on page 201, Activity 5 in the Activity Workbook.

 

  1. Answer questions 1 and 2.