Answer :
To determine how many millimeters are equivalent to one inch, we can follow these steps:
1. Recognize that one inch is standardized to be equivalent to a certain number of millimeters. This conversion factor is given by
$$
1 \text{ inch} = 25.4 \text{ mm}.
$$
2. Since we are calculating for one inch, we multiply the value of one inch by the conversion factor. That is,
$$
\text{millimeters} = 1 \text{ inch} \times 25.4 \frac{\text{mm}}{\text{inch}}.
$$
3. Performing the multiplication gives
$$
\text{millimeters} = 25.4 \text{ mm}.
$$
Thus, one inch equals $25.4$ millimeters.
The correct answer is:
$\boxed{25.4}$.
1. Recognize that one inch is standardized to be equivalent to a certain number of millimeters. This conversion factor is given by
$$
1 \text{ inch} = 25.4 \text{ mm}.
$$
2. Since we are calculating for one inch, we multiply the value of one inch by the conversion factor. That is,
$$
\text{millimeters} = 1 \text{ inch} \times 25.4 \frac{\text{mm}}{\text{inch}}.
$$
3. Performing the multiplication gives
$$
\text{millimeters} = 25.4 \text{ mm}.
$$
Thus, one inch equals $25.4$ millimeters.
The correct answer is:
$\boxed{25.4}$.
