7th Grade Math

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Volume

PART A B C DEF

Multi-Part

Lesson 1

Addresses

GLE 0706.1.3, GLE 0706.1.4,

GLE 0706.4.4.

564 Volume and Surface Area

Main Idea

Find the volumes of

cylinders.

Vocabulary

cylinder

precision

Area of a Circle

A = πr^2

A = π(5) 5 cm

2

The area

is about

78.5 cm^2.

Volume of Cylinders

Set a soup can on a piece of grid paper and trace

around the base, as shown below.

1. Estimate the number of centimeter cubes
   that would fit at the bottom of the
   container. Include parts of cubes.


2. If each layer is 1 centimeter high,
   how many layers would it take to
   fill the cylinder?


3. MAKE A CONJECTURE Write a
   formula that allows you to find
   the volume of the container.

A cylinder is a three-dimensional figure with two parallel congruent

circular bases. As with prisms, the area of the base of a cylinder tells

the number of cubic units in one layer. The height tells how many

layers there are in the cylinder.

Volume of a Cylinder

Words The volume V of a cylinder

with radius r is the area of

the base B times the height h.

Model r

h

Symbols V = Bh, where B = πr 2 B^ = πr^2

or V = π r^2 h

Volume of a Cylinder

Find the volume of the cylinder. 5 cm

8.3 cm

Round to the nearest tenth.

V = πr^2 h Volume of a cylinder

V = π(5)^2 (8.3) Replace r with 5 and h with 8.3.

Use a calculator.

[π] 5 651.8804756

The volume is about 651.9 cubic centimeters.

V

c

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