What does the prefix deca- mean in the word decathlon?

International spelling as used by the International Bureau of Weights and Measures; symbol: da) or deka- (American spelling) is a decimal unit prefix in the metric system denoting a factor of ten. The term is derived from the Greek déka (δέκα) meaning "ten".

DECATHLON: an athletic event taking place over two days, in which each competitor takes part in the same prescribed ten events (100-meter dash, long jump, shot put, high jump, 400-meter dash, 110-meter hurdles, discus, pole vault, javelin, and 1,500-meter run).

this need to be done in 15 minutes kind of passed the 15 minutes by now sorry dude but i can list some of my thoughts down for you : (