That depends. Do you want to know the highest index of the biggest, do you want a reference to the biggest, or do you want to perform an action on the biggest. You would approach it slightly differently with each objective.

Remember that evaluated in scalar context, an array gives its number of elements. Therefore, with my $count = @array; $count will contain the number of elements in @array. Check your 10 arrays that way and figure out which one is the biggest.