What is 12.171515... as a Fraction?

12.1715 equals 200831650 as a fraction.

How do you turn 12.1715 repeating into a fraction?

Detailed Answer:

Step 1: To convert 12.1715 repeating into a fraction, begin writing this simple equation:

n = 12.1715 (equation 1)

Step 2: Notice that there are 2 digits in the repeating block (15) and 2 digits in the non-repeating part (17). Multiply both sides by 10⁴ = 10000.

10000 × n = 121715.15 (equation 2)

Step 3: Now subtract equation 1 from equation 2 to cancel the repeating block (or repetend) out.

10000 × n = 121715.15
  100 × n = 12.1715
 9900 × n = 120498

1204989900 could be the answer, but it still can be put in the simplest form, i.e., reduced.

To simplify this fraction, divide the numerator and denominator by 6 (the GCF - greatest common factor).

n = 1204989900 = 120498 ÷ 69900 ÷ 6 = 200831650. So,

12.1715 = 200831650 as the lowest possible fraction.

As the numerator is greater than the denominator, we have an improper fraction, so we can also express it as a mixed number, thus 200831650 is also equal to 122831650 when expressed as a mixed number.

The repeating decimal 12.1715 (vinculum notation) has a repeated block length of 2. It is also represented as 12.17151515... (ellipsis notation) which equals approximately 12.171515151515 (decimal approximation)(*).

The recurring decimal 12.1715 can be written as a ratio of two integers having 20083 as the numerator and 1650 as the denominator. So, it is a rational number (named after ratio). It can be shown that a number is rational if its decimal representation is repeating or terminating.

(*) At present, there is no single universally accepted notation or phrasing for repeating decimals.