HP Prime Graphing Calculator - Manual (Page 189)

Geometry 185
equation
Returns the Cartesian equation of a curve in x and y, or the
Cartesian coordinates of a point.
equation(curve) or equation(point)
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 equation(GC)
returns x 2 + y 2 = 1.
extract_measure
Returns the definition of a geometric object. For a point, that
definition consists of the coordinates of the point. For other
objects, the definition mirrors their definition in Symbolic view,
with the coordinates of their defining points supplied.
extract_measure(Var)
ordinate
Returns the y coordinate of a point or the y length of a vector.
ordinate(point) or ordinate(vector)
Example:
Example: ordinate(GA) returns the y-coordinate of the
point A.
parameq
Works like the equation command, but returns parametric
results in complex form.
parameq(GeoObj )
perimeter
Returns the perimeter of a polygon or the circumference of a
circle.
perimeter(polygon)
or
perimeter(circle)
Examples:
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 perimeter(GC)
returns 2.