The radius of a circle is 12.1 in. Find the circumference \textit{to the nearest tenth}to the nearest tenth.

To find this answer, we should subtract 2 1/2 from 3 1/4. The simplest way to do this is to turn them into improper fractions, found the least common denominator, and subtract the numerators.

3 1/4=13/4
2 1/2=5/2

The least common multiple is 4, so we should multiply the numerator and denominator of 5/2 by 2.

5/2=10/4

Now we can just subtract the numerators.

13/4-10/4=3/4

Using the math above, we can see that it saves D. 3/4 hours.