Finding common factors

We had different amounts of counters (12, 18 and 24) and had to make rectangles with them so that all had the same sized width.

At first we were unsure whether this was possible or not. However, after experimenting with the apparatus we realised it could be done in numerous ways. This is because those three numbers share common factors.

Have a go at home with the following digits: 16, 28 and 32. How many different rectangles can you make that have the same sized width?