6.9
Surface Area and Volume of
Spheres
Performance Exam: TOMORROW
*You will get the review after notes*
Vocabulary
• A sphere is the set of all points in space
equidistant from a given point.
– This point is called the center of the sphere.
• A radius of a sphere is a segment from
the center to a point on the sphere.
• A chord of a sphere is a segment whose
endpoints are on the sphere.
• A diameter of a sphere is a chord that
contains the center.
Vocabulary
• A great circle is the intersection of a
sphere and a plane passing through the
center of the sphere.
– The circumference of a great circle is the
circumference of the sphere.
Vocabulary
• A hemisphere is half of a sphere, formed
when a great circle separates a sphere
into two congruent halves.
Great
Circle
Vocabulary
• Surface Area of a Sphere
S = 4πr2
• Volume of a Sphere
V = 4/3πr3
Example 1:
• Find the surface area of the sphere.
Example 2:
• The circumference of a sphere is 12π feet.
Find the surface area of the sphere.
– They give us the circumference, so we can
find the radius.
– Once we have the radius we can find surface
area.
You Try:
• If the surface area of a sphere is 324π cm2.
Find the radius of the sphere.
Example 3:
• Find the volume of the sphere.
Classwork/Homework:
• Review the possible topics for
the Performance Exam
tomorrow!