http://www.ck12.org Chapter 11. Surface Area and Volume
11.7 Spheres
Here you’ll learn how to calculate the volume and surface area of a sphere.
What if you were asked to geometrically consider a bowling ball? A regulation bowling ball is a sphere that weighs
between 12 and 16 pounds. The maximum circumference of a bowling ball is 27 inches. Using this number, find
the radius, surface area, and volume of the bowling ball. You may assume the bowling ball does not have any
finger holes. Round your answers to the nearest hundredth. After completing this Concept, you’ll be able to answer
questions like these.
Watch This
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/52634CK-12 Foundation: Chapter11SpheresA
Watch this video to learn more about the surface area of spheres.
Follow this link to watch a video about the volume of a sphere.
Guidance
Asphereis the set of all points, in three-dimensional space, which are equidistant from a point. You can think of
a sphere as a three-dimensional circle. A sphere has acenter,radiusanddiameter, just like a circle. Theradius
has an endpoint on the sphere and the other is on the center. Thediametermust contain the center. If it does not,
it is achord. Thegreat circleis a plane that contains the diameter. It is the largest circle cross section in a sphere.
There are infinitely many great circles. The circumference of a sphere is the circumference of a great circle. Every
great circle divides a sphere into two congruent hemispheres, or two half spheres. Also like a circle, spheres can
have tangent lines and secants. These are defined just like they are in a circle.