.he 'ANGLE''Page '
.fo 'Steven Hardy'- % -'June 1978'
.ce 2
The ANGLE function
==================
.sp
This new addition to the POP11 library finds the angle defined
by three points.
To make 'angle' available for use give the command:
 	: lib angle;
.br
A typical call of angle might be:
 	: angle([1 1], [1 5], [5 5]) =>
 	** 90
.br
Suppose 'angle' has been called with three points, 'a', 'b' and 'c', thus:
 	: angle(a, b, c) =>
.br
The result is the amount the turtle would have to turn
to face 'c', if it was initially at 'b' and facing 'a'.
The result will be in the range 0 to 360.
