Area of a Circle
Cut the circle into wedges, rearrange into a near-rectangle: area = πr²
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The circle area formula S = πr² comes from cutting and rearranging: slice the circle into wedges and zip them into an approximate rectangle — the finer the slices, the closer it gets. The rectangle’s width is r and its length about πr, so the area is πr². Switch between 8, 16 and 32 wedges and watch it sharpen.
Tap “Cut & rearrange”: the circle splits into sectors that zip into an approximate rectangle — the finer the cut, the closer it gets. The rectangle's length is about πr and its width is r, so S = πr². Switch between 8, 16 and 32 wedges to watch it sharpen.