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