Texas Instruments TI-89 User Manual page 32

Creating Polygons
Creating a Regular
Polygon
Note: After creating a
regular polygon, you can
move a point placed on it
along the entire perimeter of
the polygon. (See previous
page.)
Note: The polygon can have
a minimum of 3 and
maximum of 17 sides. If you
move beyond 17 sides or
180 degrees from the initial
vertex and the center point,
the convex polygon
becomes a star polygon,
and a fraction is displayed at
the center point.
Note: The minimum value is
5/2 and the maximum value
is 17/3. The numerator is
the number of sides. The
denominator is the number
of times the star is crossed.
TI-89 / TI-92 Plus / Voyage™ 200 PLT Cabri Geometry App
(continued)
The tool constructs a regular convex or star
Regular Polygon
polygon defined by a center point and n sides.
To begin creating either type polygon, perform steps 1 through 3,
then go to the appropriate step 4 depending on the type of polygon
that you want to create.
1. Press ... and select
5:Regular Polygon
2. Move the (#) cursor to the desired
location.
3. Press ¸ to create the center
point, press the cursor pad to expand
the radius, then press ¸.
The number of sides is displayed at
the center point. (Default = 6.)
To create a regular convex polygon:
4. Move the pointer clockwise from its
current position to decrease (ì) the
number of sides or counterclockwise
from its current position to increase
(+) the number of sides.
Press ¸ to complete the convex
5.
polygon.
To create a regular star polygon:
6. Move the cursor counterclockwise
from its current position until a
fraction is displayed at the center
point. Continue to move the cursor
until the desired number of sides is
reached.
7. Press ¸ to complete the star
polygon.
.
Create the center point.
Specify the radius.
Determine # of sides.
Completed polygon.
Rotate counterclockwise.
Completed polygon.
28