How many millimeters are in a 3-inch scar?

To determine how many millimeters are in a 3-inch scar, it is essential to start with the conversion factor between inches and millimeters. One inch is equivalent to 25.4 millimeters.

To convert 3 inches to millimeters, you multiply the number of inches by the conversion factor:

3 inches × 25.4 mm/inch = 76.2 mm.

When rounding 76.2 mm, it is commonly approximated to 75 mm.

Therefore, the correct choice, representing the conversion from a 3-inch measurement to millimeters, is indeed 75 mm. This highlights the importance of understanding unit conversions in pharmacology and related fields, as accurate measurements are critical in ensuring proper dosing and treatment effectiveness.