64 kilometers = 64,000 meters. (One kilometer equals 1000 meters.)
There are 1,000 meters (m) in a kilometer (km), so your 4.6 km in meters is 4.6 x 1,000 = 4,600 meters in the 4.6 km you had to start with.
In order to convert meters to kilometers you would go meters divided by 1000 = kilometers. So your answer is 0.0057104.
You can convert kilometers to meters, or square kilometers to square meters. But you can't convert kilometers (a linear unit) to square meters (a square unit).
Convert 5.7 x 10µ meters to kilometers.
778,600,000 kilometers = 778,600,000,000 meters
975,000 meters = 975 kilometers
4.5 meters = 0.0045 kilometers
27.5 kilometers = 27,500 meters
10 kilometers = 10,000 meters
553.33 meters = 0.5533 kilometers
3.4 kilometers = 3,400 meters
0.75 kilometers = 750 meters. (A kilometer is 1000 meters.)