Fundamentals of Mathematics, 2008a

445
5
8 % = 5 8 of 1% = 5
8 · 1
100
= 0.625 · 0.01
= 0.00625
7.6.2.2 Practice Set A
Exercise 7.6.1 (Solution on p. 470.)
Convert 1 4
% to a fraction.
Exercise 7.6.2 (Solution on p. 471.)
Convert 3 8
% to a fraction.
Exercise 7.6.3 (Solution on p. 471.)
Convert 3 1 3
% to a fraction.
7.6.3 Conversions Involving Nonterminating Fractions
We must be careful when changing a fraction of 1% to a decimal. The number 2 3
, as we know, has a
nonterminating decimal representation. Therefore, it cannot be expressed exactly as a decimal.
When converting nonterminating fractions of 1% to decimals, it is customary to express the fraction as a
rounded decimal with at least three decimal places.
Converting a Nonterminating Fraction to a Decimal
To convert a nonterminating fraction of 1% to a decimal:
1. Convert the fraction as a rounded decimal.
2. Move the decimal point two digits to the left and remove the percent sign.
7.6.3.1 Sample Set B
Example 7.33
Convert 2 3
% to a three-place decimal.
1. Convert 2 3
to a decimal.
Since we wish the resulting decimal to have three decimal digits, and removing the percent
sign will account for two of them, we need to round 2 3
to one place (2 + 1 = 3).
2
3 % = 0.7% to one decimal place. ( 2
3 = 0.6666 . . . )
2. Move the decimal point two digits to the left and remove the % sign. We'll need to add zeros
to locate the decimal point in the correct location.
% = 0.007 to 3 decimal places
2
3
Example 7.34
Convert 5 4
11
% to a four-place decimal.
1. Since we wish the resulting decimal to have four decimal places, and removing the percent
sign will account for two, we to round 4 11
to two places.
5 4 11 % = 5.36% to two decimal places. ( 4
11 = 0.3636 . . . )
2. Move the decimal point two places to the left and drop the percent sign. 5 4
11
% = 0.0536 to
four decimal places.
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