Area of a Circle - Wedge/Sector Demonstration
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!