BBC

Geometric skills Area of quadrilaterals

Watch this video to learn how to find the area of quadrilaterals.
BBC

Geometric skills Spliting quadrilaterals

The following quadrilaterals can be split into rectangles and triangles in order to calculate their area.
insider.si.edu

Geometric Model by A. Harry Wheeler, Triangle Transformable into Triangle Transformable into Quadrilateral Transformable into Quadrilateral, Plane Dissection

They may be arranged as a quadrilateral in two ways and as a triangle in two ways. This is model 3J in Wheeler's list of decompositions of polygons, listed with the triangles. Location Currently not ...
insider.si.edu

Geometric Model by A. Harry Wheeler, Inscribed Quadrilateral Transformable into Inscribed Quadrilaterals, Plane Dissection

This is Wheeler's model 4Q. It shows an inscribed quadrilateral in four pieces. Each piece is a section of a circle. It is divided into segments of two colors of plastic, so that there is a yellow ...