Area of a Circle - Wedge/Sector Demonstration

Topic:
Area, Circle
We know that the area of a circle is: A=πr². But this is actually hard to prove. So we cut the circle into wedges and place half of the wedges face-up and half face-down. The hanging-out yellow pieces always "fill-up" the empty areas of the rectangle with A=πr² As the number of wedges increases, the teal line -> radius and the hanging-out pieces start to fit inside the rectangle. Isn't that cool? Showing this mathematically is called calculus!