Practically speaking, the limit formula can't hide whether people find that the area of a circle is equal to 7(d/3). I've been borrowing 6x2 before? Not the area formula of a circle. Inevitable πR? And πr? There are words that are as imprecise as close, approximate, close or the like.

Because the rectangular area πR? Because the infinitesimal sector carries the vacancy angle outside the arc, it is transformed into the tangent of the circle 6x2? The area of polygon must be greater than the area of circle; πr？ With the infinite division of the small fan, the umbrella between the arc and the chord will be lost, but it will be transformed into a circle inscribed with positive 6x2. The area of a polygon must be smaller than that of a circle.

According to the axiom of area "softening" equal product deformation, it is deduced that "the area of a circle is equal to 7 times the square of 65438+ diameter d".