Lesson 12

Part III (Geometry and Animation, continued)

In this part, you will learn how to do constructions in Geometry. Usually when we create a construction, we must first select something. Watch the status bar for helpful hints.

1. Finding the Midpoint of a Line Segment

2. Evaluating the Midpoint in eActivity

3. Bisecting an Angle

4. Drawing a Tangent Line to a Curve

A “tangent” to a curve is a line that just touches the curve. Have you ever heard the saying “going off on a tangent”? Notice the tangent line goes away from the curve in either direction.

Part III


Practice Exercises

  1. Open the eActivity application and then open L12_PartIII_a.
  2. Expand the Geometry strip.
  3. Read the directions inside the eActivity.
  4. Click Resize to enlarge the Geometry window. If needed, zoom your window to show the bisected angle (use the + and – keys). Press Swap if you need to re-read the directions!
  5. With the 2nd tangent line and angle bisectors showing, get a screen capture and paste it into your Lesson12 document (under a title of PART III).
  6. Notice that when you bisected the angle formed by the tangent lines, two angle bisectors were drawn. One for each pair of vertical angles. I thought this was interesting .
  7. Return to eActivity and save your work as an eActivity named L12_PartIII_a_your initials here.
  8. Open the eActivity named L12_PartIII_b.
  9. Expand the Geometry strip.
  10. Follow the directions inside the eActivity.
  11. Get a screen capture. Add two blank spaces following the first screen capture and then paste this one.
  12. There are a few very interesting things happening as you move one of the vertices. The point where your three angle bisectors meet is called the triangle’s incenter. If you have time, look up “incenter of a triangle”.
  13. Save your work as an eActivity named L12_PartIII_b_your initials here.
  14. Clear your eActivity window and insert a Geometry window.
  15. Draw a line segment.
  16. Draw a circle to the left or above of your line segment.
  17. Select Draw/ Construct/ Reflection. Notice the status bar.
  18. Click on your line segment. Zoom to see both circles, if needed.
  19. Select just the center point of each circle. Press on a selection handle and drag to eActivity. An expression containing matrices should appear.
  20. Get a screen capture. Add two blank spaces following the second screen capture and then paste this one.

Before continuing to Part IV, please back up your Lesson 12 activities:

  1. Begin by opening the Exchange Window. [Hint: Right click on the ClassPad emulator.]
  2. Click on the + sign in front of the Active Document folder and the ClassPad Manager folder.
  3. Click on the + sign in front of the Lesson_12 file and then the eActivities folder.
  4. Next, click on the folder named Lesson 12 to see the eActivities you just completed. Are they there?
  5. Press (left click) on the Lesson 12 folder and drag it to the CP101_Backup vcp file.

Part IV

Written Exercises

Please copy and paste the following questions into your Lesson12 document (under a title of Part IV) and answer them.

  1. How do you add an animation?
  2. What does it mean to constrain something?
  3. How do you know what information is showing in the measurement box?
  4. How do you construct the midpoint of a line segment?

Reflection Exercises

You have just completed the twelfth lesson in ClassPad 101. Awesome. Please take a few moments to copy and paste the following three questions at the end of your Lesson12 document and answer them.

  1. Approximately how long did it take you to complete this lesson?
  2. Which activity did you enjoy the most?
  3. Did you find any part of this activity difficult to follow? If so, which part? Also, how did you overcome the difficulty?

Assessment 12a: Geometry and Animation

Assessment 12b: Uploading your Lesson_12.vcp file