Yes, the are proportional. To do this, just divide the distance in each example by the number of minutes. You will get 3/4 each time, so they are proportional.
For your table, just create 3 columns.
Distance Time Rate
2/3 1/4 3/4
If you make a table, you will have the same rates. If you graph the data, it will be linear through the origin. Both ways prove that it is proportional.