ALL ANIMATIONS / Cylinder from Sphere




The surface area of a sphere is opened up to illustrate how the formula surface area = 4 Π r2 can be understood. The animation starts with a lined sphere. The upper and lower hemisphere skins then open out to form the sphere's enclosing cylinder. This cylinder unwraps to demonstrate how its circumference (2Πr) and its height (2r) combine to give 4Πr2.


Buy Books by Russell Kightley


YesterdayMakers.com


EcstaticAutomata.com


LethesRoad.com


TimeAerials.com




Russell Kightley Media
PO Box 9150, Deakin, ACT 2600, Australia. Mobile phone Australia 0405 17 64 71
email RKM