14.12.9 The measure of an angle in space: angle
See Section 13.14.4 for angle measures in two-dimensional
geometry.
The angle command finds the measures of angles in space.
It can take its arguments in different ways.
Three points.
-
angle takes three arguments:
A,B,C, three points.
- angle(A,B,C) returns the measure of the undirected angle
BAC.
Example.
Input:
angle(point(0,0,0),point(1,0,0),point(0,0,1))
Output:
Two intersecting lines.
-
angle takes two arguments:
L,M, two lines which intersect.
- angle(L,M) returns the measure of the angle between
the lines L and M.
Example.
Input:
angle(line([0,0,0],[1,1,0]),line([0,0,0],[1,1,1]))
Output:
A line and a plane.
-
angle takes two arguments:
- angle(L,P) returns the measure of the angle between
L and P.
Example.
Input:
angle(line([0,0,0],[1,1,0]),plane(x+y+z=0))
Output: