| 30.9 mm * | 0.1 cm | = 3.09 cm | 
| 1 mm | 
| Units of measurement | Unit of length | 
|---|---|
| Nanometre | 30900000.0 nm | 
| Micrometre | 30900.0 µm | 
| Millimetre | 30.9 mm | 
| Centimetre | 3.09 cm | 
| Inch | 1.2165354331 in | 
| Foot | 0.1013779528 ft | 
| Yard | 0.0337926509 yd | 
| Metre | 0.0309 m | 
| Kilometre | 3.09e-05 km | 
| Mile | 1.92004e-05 mi | 
| Nautical mile | 1.66847e-05 nmi | 
