Quadrilateral Area
Quadrilateral — is a geometric figure consisting of four points (vertices), none of which lie on the same line, and four segments (sides), pairwise connecting these points. Convex and non-convex quadrilaterals are distinguished.
The area of any quadrilateral is equal to half the product of the diagonals multiplied by the sine of the angle between them.
Formula for Quadrilateral Area: 
where - d1 is the diagonal of the quadrilateral, d2 - is the diagonal of the quadrilateral, sinα - is the sine of the angle between the diagonals.