How to show the surface area of a sphere is 4πr²

A short video on how to show the surface area of a sphere with radius 'r' is 4πr². The area of a circle is πr². The surface area of the sphere is equal to 4 circles of the same radius.

Surface area of a sphere

An orange a pencil and a piece of paper

Click to see a step-by-step slideshow.

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