Altitude[A,B,C, m]
[math]\;\;[/math] A,B,C three points in space,
[math]\;\;[/math] m a margin for the base line
gives
-the altitude from C onto AB,
-the base point of the altitude, C'
-the (right) angle ∡CC'A
-base segment ABC' containing all three points
Construction: [url]http://www.geogebratube.org/material/show/id/87370[/url]
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Of particular interest to me in this construction were obtaining:
1. The altitude never floats in space; AB is extended to meet it.
2. [b]∡CC'A is correct.[/b] (the angles offered by the perpendicular bisector tool are pretend).
