1. Prisms Lesson 11-2

2. 2 Truths and a fib! A cylinder is not a polyhedron.
2. A cuboid is a type of pyramid.
3. A square pyramid has 5 faces.

3. What is a prism? A prism is a 3D figure with parallel bases
that are polygons
The name of a prism tells what the base
should be shaped like:
– Triangular prism – triangle bases
– Rectangular prism – rectangle bases
– Cube – square bases
– Pentagonal prism – pentagon bases

5. These are the facts… The bases are ALWAYS parallel & congruent.
The bases are NOT always the top and bottom.
The height is NOT always vertical.
The faces are ALWAYS rectangles.

6. What’s the difference? Surface Area Lateral Area
The area of ALL the faces
Only the area of the faces
including the bases
NOT including the
bases

7. CUBE Lateral area and Surface area
A cube is a prism. Remember that in a cube all sides are the same.
Side length is 5 inches
Lateral area=?
Lateral area=4s2=4(5)2=100in2
Total Surface area=?
Total Surface area=6s2=6(5)2=150in2

8. Volume of a Cube
Volume= area of base x height V = Bh (B= AREA of the base)
Side length is 5 inches
Area of the base=?
Height=?
Volume= ?
Area of the base=5(5) =25
Height=5
Volume= 125 cubic inches

9. Lateral Area of a Rectangular Prism5 4 8
To find lateral area: find area of 4 sides, not the parallel bases.
There are 2 sides: 5 by 8 = 2(40)=80
There are 2 sides: 4 by 8 = 2(32)=64
Lateral area = 144 sq. units

10. Total Surface Area of a Rectangular Prism Surface Area = Lateral Area + 2 times area of the base5 4 8
Lateral area = ?
LA=144 sq. units
Now calculate…2 times the area of the base!
Area of the base = 5(4) = 20
20 times 2 =40
SA = =184 sq. units

11. Volume of a Rectangular Prism
V = area of base x height V = Bh (B= AREA of the base) 5 4 8
Area of base =?
Height = ?
Volume = ?
Area of base =5 x 4 = 20
H = 8
V = 20 x 8 = 160

12. Triangular Prism Lateral Area and Surface Area6 8 5 4
Lateral area = ?
Lateral area = 3 rectangles!
Lateral area =
6(4) = 24
5(4) = 20
8(4) = 32
Total= 76
Surface Area = Lateral Area + 2 times area of the base
Area of the base=?
Triangle ½(6)(4) =12
2 triangles: 24
Total SA = = 100 sq. units

13. Triangular Prism Volume6 8 5 4
Volume = Bh
Volume = area of base x height
Area of the base=?
Triangle ½(6)(4) =12
Height of prism= ?
Height of prism= 4
Volume= (12)4=48 cubic units