What year is my monark silver king trian rocket bike i think1930 serial number Ao921002 model?

Based on the serial number and model, your Monark Silver King Triang Rocket bike is likely from the early 1950s, specifically around 1952. Monark produced a variety of bikes during this period, and the Silver King model was known for its distinctive aluminum construction. For a more precise dating, you could consult vintage bike resources or forums that specialize in Monark bicycles.