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1 vote
Turn 3.8 repeating into a fraction

User Maccesch
by
8.1k points

2 Answers

2 votes

To turn
3.(8)=3.888... into a fraction you shouls do such steps:

1 step. Set up an equation by representing the repeating decimal with a variable. Using your example, you will let x represent the repeating decimal 3.(8), so you have x=3.888... .

2 step. Identify how many digits are in the repeating pattern, or n digits. Multiply both sides of the equation from Step 1 by
10^n to create a new equation. Again, using your example, you see that the repeating pattern consists of just one digit: 8. Now multiply both sides of the equation by
10^1 = 10. Thus, you have
10x = 10 \cdot 3.888... or
10x = 38.888.....

3 step. Subtract the equation in Step One from the equation in Step Two. Notice that when we subtract these equations, our repeating pattern drops off. Therefore,
10x-x=38.888...-3.888...\\ 9x=35.

4 step. You now have an equation that you can solve for x and simplify as much as possible, using x as a fraction:
9x = 35. If you divide both sides by 9, you get
x=(35)/(9). When simplified, you get that
x=3(8)/(9).

Answer:
3.(8)=3.888...=3(8)/(9).

User Racer
by
7.6k points
6 votes
The correct answer is 35/9, or 3 8/9.

Step-by-step explanation:
Let x=3.888.... This means that 10x=38.888....

Subtracting the two, we have
(10x=38.888...)-(x=3.888...), which gives us 9x=35.

Divide both sides by 9, and we get 35/9.
User Illia Ratkevych
by
8.2k points