Pre-Algebra Demystified

PRACTICE

1. Find the volume of a rectangular solid if it is 8 inches long, 6 inches
   wide, and 10 inches high.


2. Find the volume of a cube if the side is 13 feet.


3. Find the volume of a cylinder if the radius is 3 inches and its height is
   7 inches. Usep¼3.14.


4. Find the volume of a sphere if its radius is 9 inches. Usep¼ 3 :14.


5. Find the volume of a cone if its radius is 6 feet and its height is 8 feet.
   Usep¼ 3 :14.


6. Find the volume of a pyramid if its height is 2 yards and its base is a
   rectangle whose length is 3 yards and whose width is 2.5 yards.

ANSWERS

1. 480 in.^3


2. 2197 ft^3


3. 197.82 in.^3


4. 3052.08 in.^3


5. 301.44 ft^3


6. 5 yd^3

Word Problems

Word problems in geometry can be solved by the following procedure:

 Step 1 Read the problem.

 Step 2 Decide whether you are being asked to find the perimeter, area,

or volume.

 Step 3 Select the correct formula.

 Step 4 Substitute in the formula and evaluate.

EXAMPLE
How many inches of fringe are needed for a quilt that measures 110 inches by
72 inches?

SOLUTION
Since the fringe goes along the edge, it is necessary to find the perimeter of a
rectangle 110 inches by 72 inches:

P¼2lþ2w

¼ 2 110 in:þ 2 72 in.

¼364 in:

CHAPTER 9 Informal Geometry 181