I know this isn't maths but what is the correct article for the german word ''wasserpark''. I expect it's either das or der... Thank you.

If u tell me the exact meaning if wasserpark in English then maybe I can tell u the article used for it!btw is this article Dativ,Nominativ or Akusative and is it feminine, maskulin, neutrum or plural ? If your a German student u might be knowing what am asking for ! 

der wasserpark

it is maskulin. 

If wasserpark is maskulin then the article we'll use is der so der wasserpark.