Quadrilaterals with pairs of equal opposite angles and sides
If a quadrilateral has a pair of equal opposite angles and a pair of equal opposite sides, is it a parallelogram? If not, how many shapes (convex or concave) can be formed with such property? Geogebra can help us visualize this problem! Points A, B can be dragged to change the shapes. Advanced question: Can you understand how I created this demo? What kind of circle properties did I use?