median
don steward
mathematics teaching 10 ~ 16

Wednesday, 4 November 2015

circle area

pizza considerations
a circle is actually a rectangle in disguise



(same thing)


















youtube clip
 (maybe played without sound and stop at 1:25)

several useful Geogebra applets, show how the area formula can be obtained from an infinite number of tiny sectors

this one by Anthony Or uses few words



















this shows how the area of an internal regular polygon approaches the area of the circle as the number of sides increases (Archimedes)




















alternatively, a circle is an isosceles triangle in disguise:



what will the base of the triangle be?
and the height?











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