13.16.10 Checking if an object in the plane is a parallelogram: is_parallelogram
See Section 14.13.14 for checking for parallelograms
in three-dimensional geometry.
The is_parallelogram command determines whether or not an
object is a parallelogram.
-
is_parallelogram takes one argument:
G, a geometric object or a sequence of four points assumed to be
the vertices of a quadrilateral.
- is_parallelogram(G) returns 1 if G
is a parallelogram, but not a rhombus or a rectangle, returns 2 if
G is a rhombus but not a rectangle, returns 3 if G is a
rectangle but not a square, returns 4 is G is a square, and
returns 0 otherwise.
Examples.
-
Input:
is_parallelogram(i, -1+i, -1-i, 1-i)
Output:
- Input:
is_parallelogram(1+i, -1+i, -1-i, 1-i)
Output:
- Input:
Q:= quadrilateral(1+i, -1+i, -1-i, 1-i) |
is_parallelogram(Q)
|
Output:
- Input:
P:= parallelogram(-1-i, 1-i, i, D) |
is_parallelogram(P[0])
|
Output:
Note that P[0] is a parallelogram since P is a list made
of a parallelogram and vertex D.
Input:
affix(D)
Output: