In order to convert pounds to kg you would use the following equasion: 2.205 pounds = 1 kg. To find the answer you would multiply 9 by 2.205. Therefore 9 kg is equal to approximatly 20 pounds.
Just about 4 kg...
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9 stone 7pounds is 60.3kg
128 pounds = 58.0598234 kilograms
4.2 kg is about 9 pounds 4.15 ounces.
About 4.11068 kilograms.
1lb=0.454 kg
9 stone 10 pounds is 61.7kg
9 stone 8 pounds = 60.7813776 kilograms
9stone 7 pounds = 60.3 (60.3278) kg
42.1841 kg