How to set up fixed width for td with CSS?

To set up fixed width for td with CSS, we set the width property.

For instance, we werite

<tr>
  <th style="width: 16.66%">Col 1</th>
  <th style="width: 25%">Col 2</th>
  <th style="width: 50%">Col 4</th>
  <th style="width: 8.33%">Col 5</th>
</tr>

to set the width of each th element to the width we want with the width property.