4.2 Investigate
Perspective from a Point and Perspective from a Line
A teacher affects eternity; he can
never tell where his influence stops.
—
Henry Brooks Adam (1838–1918)
- Two figures are perspective from a point
provided the lines
determined from corresponding points are concurrent. The point is called the
center.
-
Two figures are perspective from a line provided the points of intersection of corresponding sides are collinear. The line is called the axis.
Examples. The first figure illustrates triangles perspective from a point. The second figure illustrates triangles perspective from a line.
The points in red may be dragged to different locations to explore
perspectivity from a point and perspectivity from a line.
To reset to the original settings, type the letter "R" on the keyboard.
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JavaSketchpad,
a World-Wide-Web component of
The Geometer's Sketchpad.
Copyright © 1990-2001 by KCP Technologies, Inc. Licensed only for non-commercial
use.
