Find the Surface Area… - North Thurston Public Schools Areas of Pyramids . Pyramids Pyramid
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Find the Surface Area… Find the surface area of a cylinder with a diameter of 10cm and a height of 15cm. S.A. = 2r 2 + 2rh = 2(5) 2 + 2(5)(15) S.A. = 200
Transcript of Find the Surface Area… - North Thurston Public Schools Areas of Pyramids . Pyramids Pyramid
Find the Surface Area…
Find the surface area of a cylinder with a
diameter of 10cm and a height of 15cm.
S.A. = 2r2 + 2rh = 2(5)2 + 2(5)(15)
S.A. = 200
Surface Areas of
Pyramids
www.mrskimrocks.com/g10.4.ppt
Pyramids
Pyramid
Pyramid – A three dimensional figure in
which one face, the base, is any polygon
and the lateral faces are triangles that
meet at a common vertex.
vertex
Pyramids cont.
The altitude of a pyramid is the
perpendicular segment from the vertex to
the plane of the base.
The length of the altitude is called the
height. Height
h
Pyramid
Pyramids cont.
Regular Pyramid – a pyramid whose base
is a regular polygon.
Slant Height – the length of the altitude of
the lateral face.
Slant
Height
Pyramid
Formulas
Lateral Area and Surface Area of a Regular Pyramid
PL2
1
Lateral
Area Base
Perimeter Slant
Height
ALS
Surface
Area Lateral
Area
Base Area
B
Example 1: Finding Surface Area
of a Pyramid
Find the surface area of a square pyramid with base edges 5 m and slant height 3 m.
m 3
m 5
ALS
PL2
1
Questions Answers B Square
F L x w
A
What is the SLANT
HEIGHT?
What is the perimeter of
the base?
L
S = L + A
#2 Finding Surface Area of a
Pyramid
Find the surface area of a regular hexagonal pyramid with a slant height 20 in and sides 8 in.
ALS
pL2
1
in 8
in 02
in 34
Questions Answers B Square
F L x w
A
What is the SLANT
HEIGHT?
What is the perimeter of
the base?
L
S = L + A
#3 Find the surface area of:
12 m
pL2
1
Questions Answers B Square
F L x w
A
What is the SLANT
HEIGHT?
What is the perimeter of
the base?
L
S = L + A
#4 Find the surface area of:
10”
15”
10”
Questions Answers B Square
F L x w
A
What is the SLANT
HEIGHT?
What is the perimeter of
the base?
L
S = L + A
pL2
1
Surface of a Cone
Finding the Base is Easier, since it is a circle.
rrAS 2..
Surface of a Cone
Finding the Surface Area.
r = 5, h = 12
rrAS 2..
Questions Answers r
What is the SLANT
HEIGHT?
Surface of a Cone
Finding the Surface Area.
r = 5, h = 12; need l
rrAS 2..
Surface of a Cone
Finding the Surface Area.
r = 5, h = 12; need l
rrAS 2..
13169
14425
125
2
222
Surface of a Cone
Finding the Surface Area.
r = 5, h = 12; need l
rrAS 2..
90..
6525..
1355.. 2
AS
AS
AS
