Rational Cyclic Orthodiagonal Quadrilateral

​
x
5
y
6
z
1
|AB|
|BC|
|CD|
185
455
444
|DA|
|CA|
|BD|
156
480
319
An orthodiagonal quadrilateral is a quadrilateral with perpendicular diagonals or with a perpendicular pair of opposite sides (red lines).
A cyclic quadrilateral has vertices that lie on a circle (shown in black).
A rational quadrilateral has rational sides and diagonals.
If
x
,
y
,
z
are rational numbers, then two rational cyclic orthodiagonal quadrilaterals
ABCD
can be constructed, with either
AB=2xz
2
y
+
2
z

,
BC=
2
y
-
2
z
(
2
x
+
2
z
)
,
CD=(
2
x
-
2
z
)
2
y
+
2
z

,
DA=2yz(
2
x
+
2
z
)
,
CA=
2
x
2
y
-
2
x
-4xy+
2
y

2
z
+
4
z

,
BD=2(x+y)zxy-
2
z

,
or
AB=2(x+y)zxy-
2
z

2
y
+
2
z

,
BC=(
2
x
+
2
z
)
4
y
-
4
z

,
CD=xy-xz-yz-
2
z
xy+xz+yz-
2
z

2
y
+
2
z

,
DA=2yz(
2
x
+
2
z
)
2
y
+
2
z

,
CA=-
2
x
4
y
+
2
y
6
2
x
+8xy+
2
y

2
z
-
2
x
+8xy+6
2
y

4
z
+
6
z

,
BD=2xz
2

2
y
+
2
z


.
These formulas generate all such quadrilaterals. The Demonstration uses the first set of formulas.

External Links

Rational Isogonal Conjugates
Constructing a Rational Rectangle
Rational Cyclic Polygons
Seven Points with Integral Distances
Lengths of Sides and Angle Bisectors Are Rational Together
Integer Triangle of the Gergonne Point
Orthodiagonal Quadrangle (Wolfram MathWorld)
Cyclic Quadrilateral (Wolfram MathWorld)

Permanent Citation

Minh Trinh Xuan
​
​"Rational Cyclic Orthodiagonal Quadrilateral"​
​http://demonstrations.wolfram.com/RationalCyclicOrthodiagonalQuadrilateral/​
​Wolfram Demonstrations Project​
​Published: February 8, 2023