HP Prime Graphing Calculator - Manual (Page 190)

186 Geometry
If GA is the point at (0, 0), GB is the point at (1, 0), and GC
is defined as square(GA, GB-GA), then perimeter(GC)
returns 4.
radius
Returns the radius of a circle.
radius(circle)
Example:
If GA is the point at (0, 0), GB is the point at (1, 0), and GC
is defined as circle(GA, GB-GA), then radius(GC) returns 1.
Test
is_collinear
Takes a set of points as argument and tests whether or not they
are collinear. Returns 1 if the points are collinear and 0
otherwise.
is_collinear(point1, point2, …, pointn)
Example:
is_collinear(point(0,0), point(5,0),
point(6,1)) returns 0
is_concyclic
Takes a set of points as argument and tests if they are all on
the same circle. Returns 1 if the points are all on the same
circle and 0 otherwise.
is_concyclic(point1, point2, …, pointn)
Example:
is_concyclic(point(-4,-2), point(-4,2),
point(4,-2), point(4,2)) returns 1
is_conjugate
Tests whether or not two points or two lines are conjugates for
the given circle. Returns 1 if they are and 0 otherwise.
is_conjugate(circle, point1, point2) or
is_conjugate(circle, line1, line2)