HP Prime Graphing Wireless Calculator - Manual (Page 39)

Geometry 35
4. Press P to return to Plot view to see the rotated square.
Dilation A dilation (also called a homothety or uniform scaling) is a
transformation where an object is enlarged or reduced by a
given scale factor around a given point as center.
In 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 collinear with
its corresponding point on
the original triangle and point I. Further, the distance from
point I to each new point will be twice the distance to the
original point (since the scale factor is 2).
1. Tap ,
tap Transform, and select Dilation.
2. Tap the point that is to be the center of dilation and press
E .
3. Enter the scale factor and press E .
4. Tap the object that is to be dilated and press E .
Similarity Dilates and rotates a geometric object about the same center
point.
similarity(point, realk, angle, object)
Example:
similarity(0, 3, angle(0,1,i),point(2,0))
dilates the point at (2,0) by a scale factor of 3 (a point at
(6,0)), then rotates the result 90° counterclockwise to create a
point at (0, 6).
Projection A projection is a mapping of one or more points onto an
object such that the line passing through the point and its
image is perpendicular to the object at the image point.
1. Tap ,
tap Transform, and select Projection.
2. Tap the object onto which points are to be projected and
press E .