Insta Science Class on Instagram: "This video demonstrates a fascinating geometric dissection proof of the area of a regular 12-sided polygon. By drawing lines from the center to each vertex, the polygon is divided into 12 identical isosceles triangles, each with a central angle of 30° and sides equal to the circumradius R. The area of each triangle is \frac{1}{4}R^2, and multiplying by 12 gives a total area of 3R^2. Instead of relying solely on calculations, the video visually rearranges these

Concave and Convex polygon or quadrilateral

How to identify different polygons - BBC Bitesize