Smallest to biggest 0.43,3/7,43.8%,7/16

First, we need to convert all the givens to decimal numbers. This will ease the arrangement process.
0.43 is already given as a decimal
3/7 is equal to 0.428
43.8% is equal to 0.438
7/16 is equal to 0.4375

Now, it has become easy to arrange the givens from smallest to biggest as follows:
0.428 , 0.43 , 0.4375 , 0.438

Changing the decimals back to the given form, we will find that the arrangement from the smallest to the biggest is as follows:
3/7 , 0.43 , 7/16 , 43.8%