Riddles: 10 Goldsmiths and 100 rings (Question)

 

A king summons 10 goldsmiths. Each is given 100 grams of gold and is asked to make 10 rings weighing 10 grams each.

 

After 1 week all 10 goldsmiths return to the king with the finished rings. The king has heard a rumour that one of the goldsmiths has cheated him by making each ring only 9 grams.

 

The king has a scale, but can only make one weighing before it breaks down. How shall he weigh the rings to determine who the cheater is?