Answer:
5.12x10¹¹ millimeters
Explanation:
Milli is a prefix used in science and engineering to decribe the number as the exponent x10⁻³. In the prefix kilo, the number is at the exponent x10³.
5.12x10⁵ kilometers are:
5.12x10⁵ kilometers * (1000m / 1km) = 5.12x10⁸ meters
5.12x10² meters * (1m / 1000millimeters) = 5.12x10¹¹ millimeters