Approximating the Area of a circle

Use check boxes to approximate the area of a circle. Drag point B, what do you notice about the areas of the polygons in relation to the circle?

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What do you think a guess for the Area of a 64-gon would be?
Using the square's Area, can you find the radius of the circle, without the circle's Area?

Todd Majestic, Created with GeoGebra