|Area of a convex quadrilateral. Example of creating a calculator.|
This online calculator calculates area of a convex quadrilateral given diagonal values and value of angle between them. Article also describes the process of creating a calculator.
|Area of a quadrilateral|
This article lists several calculators to compute the area of a quadrilateral
|Area of a rectangle by coordinates|
This online calculator calculates area of a convex quadrilateral (rectangles too) given coordinates of four vertices (corners)