HP Prime Graphing Calculator - Manual (Page 191)

Geometry 187
Example:
is_isoscelesl(point(0,0), point(4,0),
point(2,4)) returns 3.
is_orthogonal
Tests whether or not two lines or two circles are orthogonal
(perpendicular). In the case of two circles, tests whether or not
the tangent lines at a point of intersection are orthogonal.
Returns 1 if they are and 0 otherwise.
is_orthogonal(line1, line2)
or
is_orthogonal(circle1, circle2)
Example:
is_orthogonal(line(y=x),line(y=-x)) returns 1.
is_parallel
Tests whether or not two lines are parallel. Returns 1 if they
are and 0 otherwise.
is_parallel(line1, line2)
Example:
is_parallel(line(2x+3y=7),line(2x+3y=9)
returns 1.
is_parallelogram
Tests whether or not a set of four points are vertices of a
parallelogram. Returns 0 if they are not. If they are, then
returns 1 if they form only a parallelogram, 2 if they form a
rhombus, 3 if they form a rectangle, and 4 if they form a
square.
is_parallelogram(point1, point2, point3,
point4)
Example:
is_parallelogram(point(0,0), point(2,4),
point(0,8), point(-2,4)) returns 2.
is_perpendicular
Similar to is_orthogonal. Tests whether or not two lines are
perpendicular.
is_perpendicular(line1, line2)