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 ...

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.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*R^{2}.

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

NOTE: The value of p can never be known exactly, so **surface areas** of **spheres**
cannot be calculated exactly. Common approximations for p are: 3.14, and ^{22}/7.

math2.org/math/geometry/areasvols.htm

Math2.org Math Tables: Areas, Volumes, **Surface Areas** ... Areas. square = a^{2}.
rectangle = ab. parallelogram = bh. trapezoid = h/2 (b1 + b2) ... **sphere** = (4/3) [pi]
...

www.math.com/tables/geometry/surfareas.htm

**Surface Area of a Sphere** = 4 pi r ^{2}. (r is radius of circle)

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 ...