use warnings;
use strict;

my %areas;
my $file;
my $fh;

$file = 'f2.txt';
open $fh, '<', $file or die "Can not open file $file: $!";
while (<$fh>) {
    next if $. == 1;
    my ($name, $area) = split;
    $areas{$name} = $area;
}
close $fh;

my $name_line = 0;
my $name;
my $area;
$file = 'f1.txt';
open $fh, '<', $file or die "Can not open file $file: $!";
while (<$fh>) {
    chomp;
    if ($. == 1) {
        print "$_    Area\n";
        next;
    }
    my @tokens = split;
    if (scalar @tokens == 1) {
        print "$_\n";
        $name = $tokens[0];
        $area = $areas{$name};
        $name_line = 1;
    }
    else {
        if ($name_line) {
            $name_line = 0;
            print "$_     $area\n";
        }
        else {
            print "$_\n";
        }
    }
}
close $fh;

__END__

Name  measure  Age    Area
Eric    
Test1   40     16     Texas
Test2   35     16.5 
Test3   60     27
Tets4   20     30

Dan
Test1   15     50     NY
Test2   22     70