Is 16.5 irrational yes or no

Well, a rational number is like anything like - 2,-1,0,1,2, etc. Also that includes squares like 16 or 36, and repeating decimals that either don't continue into infinity or repeat, like, 5.2, or 2.14141414 ...

irrational numbers are like pi, never-ending decimals and imperfect squares so ill say no

Yes it is irrational. Rational numbers are whole numbers such as 4, 687, 23.