11­2 Surface Areas of Prisms and Cylinders 2011
March 24, 2011
11­2 Surface Area of Prisms and Cylinders
Objective
Find the surface area of
prisms and cylinders.
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11­2 Surface Areas of Prisms and Cylinders 2011
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What is a solid?
Py
m
r
s
A
solid
is
a
a
i
mi
three‐dimensional
r
P
d
shape.
Cy What is a prism?
lin
e
A prism isd
a solid that has two congruent
bases.
n
er
Co
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11­2 Surface Areas of Prisms and Cylinders 2011
March 24, 2011
Prism
A prism is a solid that has two congruent bases.
Congruent means "same size and same shape".
The base of a prism can be any shape. You name a prism by the shape of its base.
This prism has two square bases and four rectangular faces.
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11­2 Surface Areas of Prisms and Cylinders 2011
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11­2 Surface Areas of Prisms and Cylinders 2011
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Examples of Prisms
Prism with two circular bases (Cylinder)
Prism with two pentagonal bases and
5 rectangular faces
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11­2 Surface Areas of Prisms and Cylinders 2011
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So, how do we find the
surface area of a prism?
First, "unfold" the prism so that all the surfaces lie flat. This is called making a "net".
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11­2 Surface Areas of Prisms and Cylinders 2011
Solid
March 24, 2011
Net
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11­2 Surface Areas of Prisms and Cylinders 2011
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Now, find the area of all the
separate pieces and add them
together.
Area of a prism = Area of 2 bases + Area of all faces
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11­2 Surface Areas of Prisms and Cylinders 2011
Solid
March 24, 2011
Net
6 in.
15 in.
Label the "net"
and find the
surface area
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11­2 Surface Areas of Prisms and Cylinders 2011
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6 in.
15 in.
Solid
Net
6 in.
A = 36 A = 90
6 in.
6 in.
15 in.
6 in.
6 in.
A = 90
6 in.
6 in.
15 in.
A = 90
6 in.
6 in.
15 in.
15 in.
6 in.
6 in.
A = 36 6 in.
A = 90
6 in.
6 in.
15 in.
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11­2 Surface Areas of Prisms and Cylinders 2011
6 in.
15 in.
A = 90
6 in.
March 24, 2011
A = 36 6 in.
6 in.
15 in.
6 in.
A = 90
6 in.
6 in.
Surface Area
15 in.
A = 90
6 in.
15 in.
6 in.
6 in.
A = 36 6 in.
6 in.
A = 90
6 in.
SA = 36 + 36 + 90 + 90 + 90 + 90
= 72 + 360
= 432 square inches
6 in.
15 in.
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11­2 Surface Areas of Prisms and Cylinders 2011
March 24, 2011
Find the surface area of this prism.
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11­2 Surface Areas of Prisms and Cylinders 2011
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11­2: Day 2 Surface areas on prisms and cylinders.
Warm­up
Draw the nets of each figure below. 13
11­2 Surface Areas of Prisms and Cylinders 2011
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r
e
d
n
i
yl
C
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11­2 Surface Areas of Prisms and Cylinders 2011
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. r
h
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11­2 Surface Areas of Prisms and Cylinders 2011
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. r
r
Circumference of circle (2 r)
h
h
h
Circumference of circle (2 r)
r
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11­2 Surface Areas of Prisms and Cylinders 2011
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SA of Cylinder:
r
2 (Area of Circle) + Area of Rectangle
Circumference of circle (2 r)
h
h
Circumference of circle (2 r)
r
Therefore, the formula can be simplified to:
SA = 2 r (r + h)
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11­2 Surface Areas of Prisms and Cylinders 2011
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Try One!!
h = 12 in.
r = 3 in.
r
1. Start with the formula
SA = 2 r (r + h)
h
2. Plug in the numbers
(Use = 3.14)
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11­2 Surface Areas of Prisms and Cylinders 2011
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Warm­Up
Find the Area of each Net.
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Example
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Classwork
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11­2 Surface Areas of Prisms and Cylinders 2011
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Homework
p. 611#1­3, 5­15 ﴾surface area only﴿
Try #33­35 for extra credit. You must show all your work.
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