Lesson 3

Part II (Introduction to Geometry, continued)

In this part, we will practice selecting, deselecting, resizing and measuring figures. Please think about the following as you experiment:

1. Selecting, Moving and Deselecting

Sometimes I forget to change to the selection mode and draw an unexpected figure. This is when I find Edit/Undo-Redo helpful!

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2. Resizing a Figure

You can resize a figure by selecting just part of the figure, pressing near a selection handle and dragging.

drawing a triangle

3. Measuring Angles

You can add an attached angle measure that updates as you modify the triangle.

Drawing "other" Figures

4. Using the Measurement Box to Measure Figures

The Measurement Box is very intelligent. It knows what you have selected and provides a list of all measures that it can think of related to your selection. What can the Measurement Box tell us about a circle?

5. Adding a Measure to the Window

You can display measures from the Measurement Box on the window. Simply click the top measurement button, or select Draw / Measurement / any measure. We will learn more about this in Lesson 9. For now, please try this example:

Part II


Practice Exercises

  1. Please start with a clean Geometry window. Are you ready?
  2. Draw a vector and then select it.
  3. Copy and then paste the vector (see HELP). Move the pasted vector (named s) away from the first vector (named r).
    [HELP: On your computer’s keyboard, press the Ctrl key and c key to copy the vector. Next, press the Ctrl key and v key to paste the vector. Or, you can use copy and paste from within the ClassPad’s Edit menu.]
  4. Get a screen capture and paste it into your Lesson3 document (under a title of PART II).
  5. Please clear your window and draw a circle.
  6. Advance the toolbar so that the measurement box shows.
  7. Select your circle to make the Measurement Box come to life and change it to show the circle’s circumference (the button).
    [Circumference is the distance around the outside of a circle. The ClassPad uses for distance around the outside of any figure.]
  8. Click again to display the circumference in the window.
  9. Get a screen capture. Add two blank spaces following the first screen capture and then paste this one.
  10. Please clear your window again.
  11. Draw two circles as follows: 1st draw one circle and then draw the 2nd by clicking on the 1st circle’s outer edge and then the 1st circle’s center (see the circles below).
  12. Draw line segments to create the triangle shown in the last figure below.
  13. Select two sides (you can drag to select) and click .
  14. Get a screen capture while the angle is showing in the Measurement Box. Add two blank spaces following the second screen capture and then paste this one.