11-2 surface areas of prisms and cylinders...
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112 Surface Areas of Prisms and Cylinders 2011
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Objective
Find the surface area of prisms and cylinders.
112 Surface Area of Prisms and Cylinders
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PrismWhat is a solid?
A solid is a three‐dimensional
shape.
PyramidCylinder Cone
What is a prism?A prism is a solid that has two congruent bases.
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PrismA 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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Examples of Prisms
Prism with two circular bases (Cylinder)
Prism with two pentagonal bases and 5 rectangular faces
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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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Solid Net
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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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Solid Net
15 in.
6 in.
Label the "net"and find thesurface area
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Solid Net
15 in.
6 in.
6 in.
6 in.
6 in.6 in.
6 in. 6 in.
6 in.
6 in.
6 in.
6 in.
6 in.
6 in.
6 in.
6 in.
15 in.
15 in.
15 in.
15 in.
15 in.
A = 36
A = 36 A = 90
A = 90
A = 90
A = 90
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6 in.
6 in.
6 in. 6 in.
6 in. 6 in.
6 in.
6 in.
6 in.
6 in.
6 in.
6 in.
6 in.
6 in.
15 in.
15 in.
15 in.
15 in.
15 in.
A = 36
A = 36 A = 90
A = 90
A = 90
A = 90
Surface Area
SA = 36 + 36 + 90 + 90 + 90 + 90 = 72 + 360 = 432 square inches
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Find the surface area of this prism.
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112: Day 2 Surface areas on prisms and cylinders.
WarmupDraw the nets of each figure below.
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Cylinder
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.
h
r
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h
r
r
h
Circumference of circle (2 r)
Circumference of circle (2 r)
.
h
r
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h
r
r
h
Circumference of circle (2 r)
Circumference of circle (2 r)
SA of Cylinder:
2 (Area of Circle) + Area of Rectangle
Therefore, the formula can be simplified to:
2 r (r + h)SA =
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Try One!!
h
rh = 12 in.r = 3 in.
(Use = 3.14)
1. Start with the formula
2 r (r + h)SA =
2. Plug in the numbers
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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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Homeworkp. 611#13, 515
﴾surface area only﴿
Try #3335 for extra credit. You must show all your work.
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