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The Geometer’s Sketchpad
®
for TI-89, TI-92 Plus, and
© 2000-2002 KCP Technologies, Inc.
29
Voyage™ 200 PLT User Guide and Reference Manual
existing point. This is because the existing point does not define the
circle’s radius.
Examples: Two Different Radius Points
Given two points A and B, use the
Compass tool to create a circle with
center A and radius point B.
This circle is defined as centered at
point A and passing through point B.
Moving B will change the circle’s
radius.
Imagine, however, that you had
pressed
¸
the second time in a
blank area (thus constructing point C
as shown at right) in such a way that
the circle appeared to pass through
point B. In this case, moving B will
not change the circle’s radius,
because the circle is defined by A and
C, not A and B.
Be careful to choose the defining points you want!