Search

Search results:

1.
Sum of opposite angles
$\alpha + \gamma = 180\degree$
2.
Sum of opposite angles
$\beta + \gamma = 180\degree$
3.
Ptolemy's theorem
$ac+bd=d_1d_2$
4.
Permeter
$P = a+ b+ c+ d$
5.
Circumscribed radius
$R=\dfrac{1}{4} \sqrt{ \dfrac{(ac+bd)(ad+bc)(ab+cd)}{(p-a)(p-b)(p-c)(p-d)} }, \text{ where } p = \dfrac{a+b+c+d}{2}$
6.
Area
$A = \dfrac{1}{2} d_1d_2 \sin \psi$
7.
Area
$A = \sqrt{(p-a)(p-b)(p-c)(p-d)}, \text{ where } p=\dfrac{a+b+c+d}{2}$