Final answer:
To increase the number 28 by 9%, we multiply it by 1.09, resulting in 30.52. Rounding to the nearest 10th, since the hundredths place is 2, we round down to get 30.5 as the final result.
Step-by-step explanation:
When the number 28 is increased by 9%, the result can be found by multiplying 28 by 1.09 (since 9% as a decimal is 0.09, and increasing a number by a percentage involves adding that percentage of the number to the original number). Mathematically, this would be calculated as:
28 × 1.09 = 30.52
Next, we are asked to round this answer to the nearest 10th. This requires us to look at the hundredths place, which is 2. Since it is less than 5, we round down and the rounded result is 30.5.
The procedure of multiplying and dividing by tens or powers of 10 is standardized in various scientific and mathematical computations for shifting decimal places. As part of rounding, if we encounter a digit in the first position to be dropped that is 5 or greater, we round up; otherwise, we round down. This is what we did with the resulting figure of 30.52, rounding down to 30.5. In mathematics, understanding how to properly round numbers is essential for correct data presentation.