Determining a percentage of a given number is a fundamental mathematical operation. In the specific instance of finding 30 percent of 45, the calculation involves multiplying 45 by 0.30 (the decimal equivalent of 30 percent). The result of this calculation yields 13.5. This represents the portion of 45 that corresponds to 30 percent of its total value. For example, if an item originally priced at $45 is offered with a 30 percent discount, the discount amount would be $13.50.
Understanding how to calculate percentage portions has broad applicability across various fields. In finance, it is essential for determining interest payments, calculating profit margins, and assessing investment returns. Retail businesses use it to compute discounts and sales tax. In statistics, it is utilized for analyzing data sets and interpreting survey results. Historically, percentage calculations have been used for centuries in trade, taxation, and scientific research, demonstrating their enduring importance.