Surface Area of Pyramids & Cones

1. 12.3 Surface Area of Pyramids & Cones
HW pg. 814 #4­24 evens
April 16, 2015
Bellwork
Get a dodecahedron and icosahedron from the back table.
Find the surface area of each.
Turn in bellwork to homework bin.

2. 12.3 Surface Area of Pyramids & Cones
HW pg. 814 #4­24 evens
April 16, 2015
12.3 Surface Area
Regular Pyramids:
one-half perimeter of the base *
the sum of the slant height and apothem
S.A. = ½P(l + a)
Slant Height (l)
altitude(h)
a
***before you can find the SA of a regular pyramid,
you must first identify the shape of the base and how
to find the perimeter of the base
S.A. = ½Pl + B
or
where b is the area of the base
vertex
Base

3. 12.3 Surface Area of Pyramids & Cones
HW pg. 814 #4­24 evens
April 16, 2015
5cm
7 cm
Find the surface area of each regular
pyramid.
8 cm
10 cm
base altitude is 6.9cm
a

4. 12.3 Surface Area of Pyramids & Cones
HW pg. 814 #4­24 evens
April 16, 2015
7.3 in
13 in
5 in
Find surface area.

5. 12.3 Surface Area of Pyramids & Cones
HW pg. 814 #4­24 evens
April 16, 2015
Cones:
area of the base + r*pi*slant height
S.A. = πr2 + rπl
Slant Height
r

6. 12.3 Surface Area of Pyramids & Cones
HW pg. 814 #4­24 evens
April 16, 2015
Find the surface area of each cone.
3.2 cm
1.4 cm
6.4 yd
2.6 yd

7. 12.3 Surface Area of Pyramids & Cones
HW pg. 814 #4­24 evens
April 16, 2015
5 ft
3 ft
5 ft
Find the surface area of the solid.

8. 12.3 Surface Area of Pyramids & Cones
HW pg. 814 #4­24 evens
April 16, 2015
12.3 HW
pg. 814
#4-24
evens