total surface area - mathppt.com · find the surface area of the cone below. sa ba la=+ surface...
TRANSCRIPT
Objective – To find the surface area of pyramids and cones.
10 m10 m
13 m
12 m SA BA LA= +
SurfaceArea = Base
Area + LateralArea
SA l w= • ( )1 4 bh2+10 m ( )2
( )1SA 10 10 4 10 132= • + • •
( )1SA 100 4 1302= + •
SA 100 260= +2SA 360 m=
Find the surface area of the pyramid below.
6 mSquare Base
6 m
5 m
4 m
4 Lateral Triangles+
( )( ) 4 1 b h2 •l w•
6 6•36 ( )14 6 52 • •
60=
2
2 6 5• •
Total Surface Area = 36 + 60 296 m=
Equilateral Triangular Pyramid
8 8
8 10 8 8
8
8
4
x2 2 2a b c+ =2 2 2x 4 8+ =2x 16 64+ =
16 16
x
SA BA LA= +1SA bh2= ( )1 3 bh2+
16 16− −
x 48=x 6.93≈
2x 48=
( )1 1SA (8 6.93) 3 8 102 2≈ • + • •
SA 27.72 120≈ + 2147.72 un≈
Surface Area of a Cone
SA BA LA= +
SurfaceArea = Base
Area + LateralArea
5 m5 m2SA r r= π• + π• • l
3 m
5 m5 m2SA 3 3 5= π• + π• •
SA 9 15= π+ π
SA 24= π 24(3.14)≈2SA 75.36 m≈
Find the surface area of the cone below.
SA BA LA= +
SurfaceArea = Base
Area + LateralArea
2SA r r= π• + π• • l
13 in.12 in.
2SA 5 5 13= π• + π• •
SA 25 65= π+ π
SA 90= π 90(3.14)≈2SA 282.6 in≈
5 in.
Lesson 10-5
Pre-Algebra Slide Show: Teaching Made Easy As Pi, by James Wenk © 2011