Day 2 Problems 4808

1
Day 2 Problems 4/8/08

• Tell whether the solid is a polyhedron. If so,
  identify the shape of the base(s). Then name the
  solid.
• 1. 2.
• Count the number of faces and edges.
• 3. 4.

2
9.2 Surface Area of Prisms and Cylinders

• A prism is a polyhedron with two congruent faces
  that lie in parallel planes.
• To picture the surface area of a prism, imagine
  unfolding it so that the prism lies flat.
• The flat representation of the faces is called a
  net.
• The surface area of a polyhedron is the sum of
  the areas of its faces.
• The surface area of a prism is equal to the area
  of its net.

3
Use the Net of a Prism

• Find the surface area of the rectangular prism.
• Add the areas of all the faces to get the surface
  area.
• S 40 40 24 24 15 15 158 in.2

8 in.
5 in.
3 in.
4
Lateral Faces and Area

• Lateral faces - the faces of the prism that are
  not bases.
• Lateral Area - the sum of the areas of lateral
  faces.

Base
Lateral Faces
Base
5
Surface Area of a Prism

• Surface Area 2 (area of base) (perimeter of
  base)(height).
• S 2 B Ph

h
w
l
6
Find Surface Area of a Prism

• Find the surface area of the prism.
• Solution.
• Find the area of a triangular base.
• Find the perimeter of a base.
• Find the height of the prism. In the diagram, h
  2.
• Use the formula for surface area of a prism.
• S 2B Ph
• 2 6 12 2
• 12 24
• 36
• The surface area of the prism is 36 square meters.

5 m
3 m
2 m
4 m
7
More Practice!!!!

• Textbook p. 485 1 3, p. 487 1 10
• Finish problems for homework