Quadrangle area

A quadrilateral is a polygon with four vertices and four sides. No three vertices of a quadrangle lie on one straight line Distinguish between convex and non-convex quadrangles

Area of a quadrangle through diagonals and the angle between them
Diagonal of a quadrilateral d1
Diagonal of a quadrilateral d2
Angle between diagonals α

The formula for calculating the area of a quadrilateral, through the diagonals and the angle between them:

S=1​/2d1d2sinα

Area of a quadrilateral through the sides and the corners between these sides
Side а
Side b
Side c
Side d
Angle between sides α°
Angle between sides β°

Formula for calculating the area of a quadrilateral in terms of its four sides and the angles between these sides:

p – perimeter of a quadrilateral divided by two.