Page 16 - Math Course 2 (Book 2)

Geometric Volume: Prisms and Cylinders
Mo. 7

Lesson 3
Let’s Begin

KEY CONCEPTS:
1. Find volumes of prisms. Volume of a Triangular Prism
2. Find volumes of cylinders.
Example

Find the volume of the triangular prism.
MO. 7 - L3a

Volumes of Prisms
12 cm

Vocabulary A-Z 25 cm

Let us learn some vocabulary 10 cm

V = Bh Volume of a prism
1
1 B = (10)(12), h = 25
= (10)(12)(25)
find volumes of prisms 2 2
If a prism has a volume of V cubic units, a height = 1500 Simplify.
of h units, and each base has an area of B square
units, then V = Bh. The volume of the prism is 1500
Answer
cubic centimeters

Real World Example

h The weight of water is 0.036 pounds times the
Area of base = B volume of water in cubic inches. How many
pounds of water would fit into a rectangular child’s
pool that is 12 inches deep, 3 feet wide, and 4 feet
Key Concept long? 12 in.

First, convert feet to inches.
Volume of a Prism 3 feet = 3×12 or 36 inches 4 ft
4 feet = 4×12 or 48 inches
3 ft
If a prism has a volume of V cubic units, a height
of h units, and each base has an area of B square To find the pounds of water that would fit into the
units, then V = Bh. child’s pool, find the volume of the pool.
V = Bh Volume of a prism
Area of base = B = 36(48)(12) B = 36(48), h = 12

= 20,736 The volume is 20,736 cubic inches.
Now multiply the volume by 0.036.
20,736 × 0.036 ≈ 746.5 Simplify.
h A rectangular child’s pool that is
12 inches deep, 3 feet wide, and
Answer
4 feet long, will hold about 746.5
pounds of water.

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