Iowa is a proportional delegate state. Cruz won 8 votes, Trump won 7 votes, and rubio won 7 votes.
Hardly what I would call any sort of real victory, more like a three-way tie.
Yep, all are proportional until Florida on March 15th the first state that is winner-take-all with 99 delegates. Last I looked, Trump was at 48% and winning big in Florida.