The Geometer’s Sketchpad
®
for TI-89, TI-92 Plus, and
© 2000-2002 KCP Technologies, Inc.
38
Voyage™ 200 PLT User Guide and Reference Manual
3. Try defining a variation of the PerpBisector tool in which you select
not only the endpoints and bisector, but the segment and midpoint as
well. This tool, given two points, will produce three results instead of
one: the segment, its midpoint, and the bisector.
4. Try defining other tools to construct triangles (given three points),
squares (given two points defining an edge), centroids or other special
points in a triangle (given three points), or a tool for any construction
you might use repeatedly.
What Can Go Wrong
When you choose Create New Tool to define a custom tool, you may see
the following message:
This message appears when the selected objects do not define a
construction—when the results you’ve selected are not completely
specified (constructed by) the givens you’ve selected. If you’re uncertain
which objects you need to select as givens, the easiest approach is to define
your example in a new (otherwise empty) sketch. Then press
ƒ
Edit:
z
Select All before creating your new tool. This will guarantee that
you’ve selected appropriate givens. From there, experiment with defining
other tools by selecting fewer and fewer objects in the sketch.
Use the Edit Tools command on the custom tools pop-up menu to present
the Edit Tools dialog box. This dialog box allows you to delete tools
you’ve created, or to save collections of them as toolkits and reopen saved
tools from existing toolkits. By saving collections of tools as toolkits, you
can distribute tools you create to others using VAR-LINK. (See the
guidebook for your handheld device at education.ti.com/guides for
instructions on using VAR-LINK to transmit saved toolkit variables
between graphing calculators.)
Once a tool has been defined, it stays in memory and appears in the custom
tools pop-up menu until you delete it. Before deleting, you can save
individual tools or collections of tools. At any time, you can reopen saved
tools and add them to your custom tools pop-up menu. (Like newly created
tools, reopened tools remain available until you delete them.)
The Edit Tools dialog box works like the VAR-LINK screen. It displays a
list of all open custom tools (i.e., all custom tools in your Custom tool pop-
up menu), with one tool active. Use:
C
and
D
To change the chosen tool in the list.
„
√√
To check or uncheck the current chosen tool.
…
All
To check or uncheck all tools in the list.
ƒ
Manage
To delete or save the currently checked tools, or to
re-open saved tools.
¸
To leave the Edit Tools dialog box.
You can also use
ƒ
Edit:
{
Select Parents when
your results are selected to
see the objects that define
them. Repeatedly choosing
Select Parents will select
the independent points that
ultimately define your
desired results.
Editing Custom
Tools
Periodically delete unused
tools to avoid filling up
memory.
You only need to (re)open
toolkits if you’ve deleted
their tools from the custom
tools menu, or if you’ve
received the toolkit from
another graphing calculator
using VAR-LINK.