PHP: foreach() loop

PHP: Circumference of planets table with alternating rows

$rad=array(
  'mercury' => 1516,
  'venus' => 3760,
  'earth' => 3959,
  'mars' => 2104,
  'jupiter' => 42982,
  'saturn' => 35615,
  'uranus' => 15700,
  'neptune' => 15256,
);

echo "<table border='1' width='300' >";
echo "<tr><td>Planet</td><td>Radius (mi)</td><td>Circumference (mi)</td></tr>";
foreach($rad as $key => $val){
  $cir=(2*M_PI)*$rad[$key];
  if($key == 'venus' || $key == 'mars' || $key == 'saturn' || $key == 'neptune'){
      echo "<tr><td><b>";
      printf("%s", $key);
      echo "</b></td>";
      echo "<td><b>";
      printf("%.2f", $val);
       echo "</b></td>";
     echo "<td><b>";
      printf("%.2f",$cir);
      echo "</b></td></tr>";
     
   }
  else{
      echo "<tr><td>";
      printf("%s", $key);
      echo "</td>";
      echo "<td>";
      printf("%.2f", $val);
      echo "</td>";
      echo "<td>";
      printf("%.2f",$cir);
      echo "</td></tr>";
     
    }

}

echo "</table>";

//Result

Planet	Radius (mi)	Circumference (mi)
mercury	1516.00	9525.31
venus	3760.00	23624.78
earth	3959.00	24875.13
mars	2104.00	13219.82
jupiter	42982.00	270063.87
saturn	35615.00	223775.64
uranus	15700.00	98646.01
neptune	15256.00	95856.28