Surface Area of a Cube

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Surface Area of a Cube Rectangular Prism

• By
• Bernice Marcelino

2
In order to know if the wrapper on the left can
be used to wrap the box on the right, what do we
need to know?
 
10 in
10 in
10 in
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Surface Area

• The surface area of a solid is the sum total of
  the areas of the polygonal regions that make up
  the solid.
• (Click on the highlighted words to know their
  definition)

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Surface Area

• We need to remember only 3 words to get the
  surface area of a 3-dimensional figure
• Polygons
• Area
• Sum

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• Before proceeding, make sure you have activity
  sheet 3 with you.

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Cube
Click on the polygon that makes up the faces
of a cube.
After clicking on the correct answer, write it in
on your activity sheet.
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Now that you have identified the polygon that
makes up the faces of a cube, its time to
identify the area.

• Which of the following is the formula for the
  area of a square?
• 4 x s s x s (b x h)/2

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Now that you have identified the polygon that
makes up the faces of a cube, its time to
identify the area.

• Which of the following is the formula of the area
  of a square?
• 4 x s s x s (b x h)/2

Sorry Try Again. 4 x s is the formula for
perimeter of a square.
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Now that you have identified the polygon that
makes up the faces of a cube, its time to
identify the area.

• Which of the following is the formula of the area
  of a square?
• 4 x s s x s (b x h)/2

Sorry Try Again. (b x h)/2 is the formula for
area of a triangle.
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Good! Now count the number of equal faces a cube
has. Just press the down arrow.
6
2
1
5
4
3
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• With the information that you have, fill up the
  chart on your activity sheet.
• Remember write ALL the polygons!

Polygon Area






SUM
HELP!
Click here to check your work.
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• Polygon Square
• Area Area of a square (s x s)
• Sum (s x s) (s x s) (s x s)
• (s x s) (s x s) (s x s)

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The surface area of a cube

• Since there are six equal faces of a cube, we can
  write the formula as
• SA 6 x s x s

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What are the dimensions of a rectangular prism?
height
width
length
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How many parallel and equal faces does a
rectangular prism have? (press down arrow to
count)
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To know the dimensions, just place the cursor on
the edge of the figure.

























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Now that you have the polygons and the
dimensions, try to fill in the other chart in
your activity sheet with the information at hand.

Click here to see again the faces and the
dimensions of a rectangular prism.
Click here to check your work
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SUM

• The answer in an addition problem.
• Ex. Find the sum of a, b and c.
• Answer a b c

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Area

• The number of square units enclosed by a
  geometric figure.
• Example Area of a rectangle l x w

w
l
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Your table should have the following entries.
Example
Polygon Area







s x s
Square
Square
s x s
Square
s x s
s x s
Square
s x s
Square
s x s
Square
(s x s)

(s x s)
(s x s)
(s x s)


(s x s)
Sum(Surface Area)


(s x s)
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You have to write down all the polygons that make
up the surface of the cube.
Example
Polygon Area
square s x s





SUM
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Polygon Area
rectangle l x w
rectangle l x w
rectangle w x h
rectangle w x h
rectangle h x l
rectangle h x l
SUM 2 (l x w) 2 (w x h) 2 (h x l)
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• Now that you know the formula for both cube and
  rectangular prism its time to answer this

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In order to know if the wrapper on the left can
be used to wrap the box on the right, what do we
need to know?
 
10 in
10 in
10 in
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Youre right! In order for us to know if the
wrapper is enough, we need to know the surface
area of the box and the area of the gift wrapper.
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20 in
 
10 in
36 in
With the given dimensions, answer the previous
question.
10 in
10 in
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What is the area of the wrapper? 720 sq. in What
is the surface area of the box? 600 sq.in
answer
answer
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Now we know that the wrapper can be used to wrap
the box because _______________ For your
seatwork pages __ in your textbook
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The End!!!
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Polygonal Regions
A region bounded by a polygon.
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The faces of a cube are all made up of squares.
A square is a quadrilateral having 4 congruent
sides.
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Try Again!!!
That polygon is a rectangle. A rectangle is a
quadrilateral having only two pairs of parallel
congruent sides.
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Try Again!!!
That polygon is a rhombus.