To find the perimeter of a rectangle, you can use the formula:
\[ \text{Perimeter} = 2 \times (\text{length} + \text{width}) \]
In this case, the height (or length) of the rectangular piece of plastic is 1 millimeter and the width is 10 millimeters. Plugging these values into the formula gives:
\[ \text{Perimeter} = 2 \times (1 , \text{mm} + 10 , \text{mm}) = 2 \times 11 , \text{mm} = 22 , \text{mm} \]
Therefore, the perimeter of the rectangular piece of plastic is 22 millimeters.