3 meters.
109 (one billion)
"Deci" is an SI prefix indicating "1/10", so a decimeter is a tenth of a meter.
1 nanometre = 0.000000001 metres. To convert a value in nanometres to metres, multiply by 0.000000001.
0.000001 mm is 1 nm. This is because the nanometer is much smaller than the mm. there are 1 million nm in a mm.