Transcript Chapter 11.2 Surface Areas of Prisms and Cylinders

Chapter 11.2 Surface Areas of
Prisms and Cylinders
Vocabulary
• Prism = a polyhedron with exactly two
congruent, parallel faces, called bases.
Other faces are lateral faces. You name a
prism by the shape of its bases
Examples:
• Right prisms
Oblique Prisms
Vocabulary
• Altitude = perpendicular segment that joins
the planes of the bases
• Height = the length of altitude
Vocabulary
• Lateral area = the sum of the areas of the
lateral faces
• Surface area = sum of the lateral area and
the area of the two bases
Theorem 11.1 lateral and Surface
Areas of a Prism
• The lateral area of a right prism is the product of
the perimeter of the base and the height
• P = perimeter of base
• H= height
L. A.  ph
Theorem 11.1 lateral and Surface
Areas of a Prism
• The surface area of a right prism is the sum of the
lateral area and the areas of the two bases
• B= area of base
S . A.  L. A.  2 B
Example #1
• Find the lateral area and total surface area
of the prism
Theorem 11.2 lateral and Surface
Areas of a Cylinder
• The lateral area of a right cylinder is the product
of the circumference of the base and the height
of the cylinder
L. A.  2rh
Theorem 11.2 lateral and Surface
Areas of a Cylinder
• The surface area of a right cylinder is the sum
of the lateral area and the areas of the two
bases
S . A.  L. A.  2 B
S . A.  2rh  2r
2
Example #1
• Find the lateral surface area of a cylinder
with a base radius of 3 inches and a height
of 9 inches.
• L. S. A. = 2π(3)(9) = 54π inches2
Example #2
• Find the total surface area of a cylinder
with a base radius of 5 inches and a height
of 7 inches
• T. S. A. = 2π(5)(7) + 2π(5)2 = 70π + 50π
= 120π inches2
Important
• You need to know the concept of lateral
face and surface area.
• For the right prisms, you know that the
lateral surface is a rectangle, you know the
area of the rectangle and you can then
multiply by however many there are.
Classwork/Homework
• Pgs 611-613 #1-16, 34