The Math Forum

 CIGS = Corner for Interactive Geometry Software

The Geometer's Sketchpad
Introductory Lab - page 4

Mike Riedy

TOC || Page 2 || Page 3 || Page 4 || Page 5 || Page 6 || Page 7

Part III: Other Useful Functions

A New Sketch:

You now need a new, blank sketch to work with. Choose "New Sketch" under the FILE menu.

What is the keyboard shortcut for starting a new sketch? ________________

A new page appears with the title "Untitled #2". The computer calls each new sketch "Untitled .." until you save it and give it a name. Let's check to make sure your snowman has the proper name. If you go to the WORK menu you should see the names of two sketches at the bottom of the list: "Untitled #2" and "Snowman." Choose "Snowman."

Now your snowman sketch should be on the screen. You can use the WORK menu to skip between any open sketches. Go back to the untitled screen.


The most important thing in GSP is how to highlight objects. This is your way of telling the computer, "I'm talking about this object." To highlight you must use the select tool. The computer tells you a straight object or a circle is highlighted by putting little black squares on the object. A point is highlighted when it looks like a bullseye.

  1. On your new sketch, draw several points. Notice that the last point you drew is highlighted.

  2. Draw a circle and two segments that start outside the circle and pass through it.

  3. Use the select tool to move the circle just a little bit but still intersecting the segments.

What if you want to move more than one thing at a time? To highlight more than one thing at a time you need to hold down the shift key while highlighting all the objects. The previous sentence is bolded because it is extremely important. Now highlight the circle and one of the segments. Move them away from the second segment so that the second segment and the circle no longer intersect.

Hiding Objects:

Very seldom when using GSP will you delete objects. Instead you will hide them. Delete means to completely erase something, while hide means that it's still there but you just can't see it. Look through the menus to find the "Hide" command.

What menu was it under? ________________

What is the keyboard shortcut? ________________

Highlight the circle and hide it using either the menu or the keyboard shortcut. The circle should disappear. Suppose you really didn't want the circle to be gone because you miss it like a long-lost brother. To bring it back you need to use the "Show All Hidden" command under the DISPLAY menu. Your long-lost brother the circle should reappear.

Changing Labels:

There will be a time where you will want to change the label the computer gave to an object in your sketch. Click once on the circle with the labelng tool (see p. 4 for a refresher).

What label did the computer give your circle? _________________

You probably don't like that label so let's change the label of your circle to "Herb the Circle." As you move the labeling tool close to the circle it turns black. As you move the lableling tool close to the actual label a small capital "A" should appear on the little white hand. When this happens double-click the mouse button. This may take some practice.

If you double-clicked properly, the screen below should appear. Type in "Herb the Circle" and click "OK".

Using the method above, change the labels of the endpoints of the segments W, X, Y, and Z in any order. If you don't like the font type or size you can change them by clicking on "Style" on the Relabel screen. You can also move the label around the object for which it is named. When you move the lableing tool close to a label you get the small "A" on the hand.

If you click and hold the mouse button, you can move the label where you want it. Try moving some labels. Save this sketch to your disk as "Herb" (see p. 5 for a refresher on saving).

Next Page

[Privacy Policy] [Terms of Use]

Home || The Math Library || Quick Reference || Search || Help 

© 1994- The Math Forum at NCTM. All rights reserved.