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Reflection
Dilation
Geometry
5. Tap the object to be
moved and press
E
.
The object is moved the
same length as the
vector and in the same
direction. The original
object is left in place.
Reflection is a transformation
in which a copy of an object
is made and every point on
the new object is the same
distance from a symmetry
axis (or mirror line) as the
original point. In the
example at the right, the
original triangle D is reflected an imaginary symmetry axis
that passes through point I.
1. Tap
and select
2. Tap a point that will be in the symmetry axis (that is,
mirror line) and press
3. Tap the object that is to be reflected across the symmetry
axis and press
symmetry axis defined by the point created at step 2.
Dilation is a transformation where an object is enlarged or
reduced by a given factor around a given center point. The
factor is sometimes referred to as the homothetic ratio (or
scale factor) and the center point is called the homothetic
center (or center of dilation).
the illustration at the right,
the scale factor is 2 and the
center of dilation is
indicated by a point near the
top right of the screen
(named I). Each point on the
new triangle is in line with its
corresponding point on the
original triangle and point I. Further, the distance from point I
Reflection
E
.
. The object is reflected across the
E
.
149
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