use strict;
use warnings;

while( my $line = <DATA>) {
  next unless $. > 12;     # $. contains current line number
  next if $line =~ /^$/;      # skip blank lines
  chomp $line;            # remove end-of-line character
  $line =~ s/\s+//;       # strip leading whitespace
  
  my @columns = split(/\s+/, $line);    # split columns on whitespace
  my $format = "%8.3f" . "%10.3f"x(@columns-3) . "\n";
  printf $format, @columns[2..$#columns];
}

# my guess at the input data
__DATA__
SKIP 1
SKIP 2
SKIP 3
SKIP 4
SKIP 5
SKIP 6
SKIP 7
SKIP 8
SKIP 9
SKIP 10
SKIP 11
SKIP 12
Line_1 0.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0
Line_2 0.0 0.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0
Line_3 0.0 0.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 1.0
Line_4 0.0 0.0 4.0 5.0 6.0 7.0 8.0 9.0 1.0 2.0
Line_5 0.0 0.0 5.0 6.0 7.0 8.0 9.0 1.0 2.0 3.0