Answer:
A. In electronic devices like mobiles, laptops, computers, TVs, etc. In stationery items like books, copies, chart-papers, etc. By above definition, square , rectangle, trapazoid, kite, rhombus, rhomboid, etc i.e every shape you can imagine with 4 sides is a quadrilaterals. Everything from blueprints (of homes) , doors, window, swimming pool, boxes, football ground, paper etc. is generally made up of such quadrilaterals.
B.
Quadrilaterals had very powerful properties that helped ancient painters, architects and designers to discover many things in the field of art, design and architecture. For example, the property of the diagonal of rectangle forming two congruent triangles lead to the construction of The Great Pyramid by the Egyptians. The list goes countless as we can't imagine the world without quadrilaterals. Wherever you see four sides, quadrilateral is involved there.
