That answer is correct.
1.609344*1012 millimetres
0.001 gigameters how did you work the problem to get the answer?
1012 (1 000 000 000 000)
A kilometer has a million millimeters; therefore, one square kilometer has a million millions (1012) square millimeters.
1 meter=1.0x10^-9 gigameters
3,900,000,000 meters
There are 100,000,000 gigameters in 100,000,000,000 micrometers. To convert micrometers to gigameters, you would divide by 10^13, since 1 gigameter is equal to 10^9 meters and 1 meter is equal to 10^6 micrometers.
1 gigameter = 1.0 × 1018 nanometers
Light travels approximately 299,792 kilometers in one second. This is equivalent to 299.792 megameters or 0.299792 gigameters per second.
1 meter = 1.0 × 10-9 gigameters
The answer you calculated is clearly WRONG! 200mm = 0.2 metres or 2*10-1 metres = 2*10-4 kilometres = 2*10-7 megametres = 2*10-10 gigametres.
1012