when you need to have the same height for 2 divs and one div has dynamic content, just add a simultaneously class to each div and the shorter div increases in height to match the larger div.

dynamic_height.js

<script type="text/javascript">
  
  $(document).ready(function(){
  
  var maxHeight = 0;
  
  $('div.simultaneously').each(function(index){
  if ($(this).height() > maxHeight)
  {
  maxHeight = $(this).height();
  }
  });
  
  $('div.simultaneously').height(maxHeight);
  
  });
  
  
</script>