Bell Ringer: Fractions Write the answer in simplest form.

1.

2.

3.

4.

5.

6.

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Lesson 9-4

Spheres

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Spheres

A sphere is formed by revolving a circle about its diameter.

In space, the set of all points that are a given distance from a given point, called the center.

Definition:

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Spheres – special segments & lines

Radius: A segment whose endpoints are the center of the sphere and a point on the sphere.Chord: A segment whose endpoints are on the sphere.

Diameter: A chord that contains the sphere’s center.

Tangent: A line that intersects the sphere in exactly one point.

Radius

Chord

Diameter

Tangent

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Surface Area & Volume of Sphere

343rVolume (V) =

Surface Area (SA) = 4 π r2

r

Example: Find the surface area and volume of the sphere.

12 cm

2 2

3 3

. 4 12 5764 12 23043

S A cm

V cm

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Great Circle & HemisphereGreat Circle: For a given sphere, the intersection of the sphere and a plane that contains the center of the sphere.

Hemisphere: One of the two parts into which a great circle separates a given sphere.

Great Circle

Hemisphere

Find the Surface area and Volume of each sphere.

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1. 2.

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Surface Area & Volume of Hemisphere

Find the surface area and volume of the following solid (Hemisphere).

10 cm2

2

3

3

. 4 10 400400. 200

24 10 1333.33

1333.3 666.72

S A of Sphere

S A of Hemisphere cm

V of Sphere

V of Hemisphere cm

Homework Pg. 520

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