26.15.10 Checking whether an object in the plane is a parallelogram
See Section 27.11.14 for checking for parallelograms
in 3D geometry.
The is_parallelogram
command determines whether or not an object is a parallelogram.
-
is_parallelogram takes
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
| is_parallelogram(i,-1+i,-1-i,1-i) |
| is_parallelogram(1+i,-1+i,-1-i,1-i) |
| Q:=quadrilateral(1+i,-1+i,-1-i,1-i); is_parallelogram(Q) |
| P:=parallelogram(-1-i,1-i,i,D); is_parallelogram(P[0]) |
Note that P[0] is a parallelogram since P is a list made
of a parallelogram and vertex D.