How many square millimeters are there in one square centimeter?

To determine how many square millimeters are in one square centimeter, it's important to first understand the relationship between millimeters and centimeters.

One centimeter is equal to 10 millimeters. When it comes to converting square measurements, we need to square that conversion factor.

Thus, if 1 cm = 10 mm, then:

1 cm² = (10 mm) × (10 mm) = 100 mm².

This means that there are 100 square millimeters in one square centimeter, making the correct answer 100 mm².

Understanding this conversion is crucial because it applies not just to this question but also to other situations where you need to work with different metric units of area, reinforcing the importance of recognizing the role of squaring in unit conversions.