en.wikipedia.org/wiki/Sphere

A sphere is a perfectly round geometrical object in three-dimensional space that is the surface of a completely round ball Like a ...

www.mathopenref.com/spherearea.html

Animated demonstration of the sphere suurface area calculation.

www.varsitytutors.com/hotmath/hotmath_help/topics/surface-area-of-a-sphere

The Greek mathematician Archimedes discovered that the surface area of a sphere is the same as the lateral surface area of a cylinder having the same radius ...

www.math.hmc.edu/funfacts/ffiles/20004.2-3.shtml

From the Fun Fact files, here is a Fun Fact at the Medium level: Surface Area of a Sphere. The area of a disk enclosed by a circle of radius R is Pi*R2.

www.teacherschoice.com.au/Maths_Library/Area%20and%20SA/area_2.htm

This topic is part of the TCS FREE high school mathematics 'How-to Library', and will help you to find the surface area of spheres, or the radius if the surface ...

math2.org/math/geometry/areasvols.htm

Surface Areas. cube = 6 a2. prism: (lateral area) = perimeter(b) L (total area) = perimeter(b) L + 2b. sphere = 4 [pi] r2. Supporters: Online Education ...

www.virtualnerd.com/pre-algebra/perimeter-area-volume/surface-area/lateral-surface-areas-examples/sphere-lateral-surface-areas

www.khanacademy.org/math/basic-geo/basic-geo-volume-sa/volume-cones/v/volume-of-a-sphere

The formula for the volume of a sphere is V = 4/3 πr³. See the formula used in ... Studying for a test? Prepare with these 4 lessons on Volume and surface area.

brilliant.org/wiki/surface-area-sphere

To prove that the surface area of a sphere of radius r is 4πr2, one straightforward method we can use is calculus. We first have to realize that for a curve ...

www.mathsteacher.com.au/year10/ch14_measurement/19_sphere/20sphere.htm

A sphere is a body bounded by a surface whose every point is equidistant (i.e. the same distance) from a fixed point, called the centre. For example, a shot (a ...