Your have 2 problems in your code.
One problem is that you are only assigning c once, when you are running the first while, it's counting C up and then when you get to the second do{}while() it's allready at the maximum.
you should "reset" C after The first while loop like here:
<th>Degrees Fahrenheit</th>
<?php
$c = $one - 1;
Secondly your only counting your f variable once, you should either make a function for it (might be overkill in this case) or move your calculation of f down inside the while loop, the last part of your code would be something like this Degrees Fahrenheit
<?php
$c = $one - 1;
do {
$f = (1.8 * $c) + 32;
$c++;
echo "<td>" . $f . "</td>";
} while ($c < $two);
$k = $x - 273;
?>
</tr>