The Correct Answer and Explanation is:
The correct answer is D) 252 mm.
To determine how many millimeters are in 25.2 centimeters, it is essential to understand the relationship between these two units of length within the metric system. The metric system is a decimal based system, which means conversions between units are based on powers of 10, making calculations straightforward.
The fundamental conversion factor to remember is that there are exactly 10 millimeters (mm) in 1 centimeter (cm). You can visualize this on a standard ruler. The numbered marks typically represent centimeters, and the smaller, unnumbered marks between them represent millimeters. You will always find ten of these smaller millimeter intervals within each single centimeter interval.
With this conversion factor in mind, we can set up the calculation. Since we are converting from a larger unit (centimeters) to a smaller unit (millimeters), we anticipate that the final number will be larger. This requires multiplication. To find the equivalent value in millimeters, we multiply the given number of centimeters by 10.
The calculation is as follows:
25.2 cm × 10 mm/cm = 252 mm
Another way to think about this multiplication is by simply moving the decimal point. Multiplying a number by 10 is equivalent to moving its decimal point one place to the right. For the number 25.2, moving the decimal point one position to the right gives us 252.
The other options are incorrect because they represent common conversion mistakes. Options A and C result from incorrectly dividing by 10 or 100, which would be the operation used when converting from a smaller unit to a larger one (like millimeters to centimeters). Option B involves an incorrect conversion factor altogether. Therefore, 25.2 centimeters is equal to 252 millimeters.
