Preview Of Geometry - Texas Instruments TI-89 User Manual

Preview of Geometry

Create a circle and construct a perpendicular line that is tangent to the circle.
Steps
1. Start a new geometry session.
In this example, G2 is the name of the
variable. You can use up to eight
characters to name constructions
(variables).
2. Create a circle.
Pressing ¸ the first time defines
the center point. Pressing ¸ the
second time draws the circle.
3. Construct a segment from the
center of the circle and attach it
to the circumference.
4. Construct a line perpendicular
to the segment at the
intersection point of the
segment and the circle.
Observe each displayed message
before pressing ¸ .
The resultant perpendicular line is
tangent to the circle.
5. Observe what happens when the
endpoint of the segment is
dragged around the circle.
TI-89 / TI-92 Plus / Voyage™ 200 PLT Cabri Geometry App
TI-92 Plus /
TI-89 Voyage™ 200
Keystrokes PLT Keystrokes
O O
© ©
3 3
¸ ¸ D G 2
D G j 2 ¸ ¸
¸ ¸
... 1 ¸ ... 1 ¸
B (hold B (hold
momentarily to momentarily to
expand the expand the
circle) ¸ circle) ¸
„ 5 A (until „ 5 A (until
you see "THIS you see "THIS
) )
POINT" POINT"
¸ A (until ¸ A (until
you see "ON you see "ON
)
THIS CIRCLE" THIS CIRCLE"
¸ ¸
† 1 ¸ † 1 ¸
¸ ¸
Press and hold Press and hold
j then press ‚ then press
C E
Display
)
2