It's the same thing. Dotted notes can be used in any time signature. The dotted crotchet signifies that the rest is for a crotchet and a quaver. If it fits the measure, it can be used, like in your example:

[![enter image description here][1]][1]

But you can also use two rests, a crotchet and a quaver:

[![enter image description here][2]][2]

If the grouping is 3-3-3 (quavers), I think the former case is more likely to appear. [1]: https://i.sstatic.net/mIKeZ.jpg [2]: https://i.sstatic.net/6WrIf.jpg

It's the same thing. Dotted notes can be used in any time signature. The dotted crotchet signifies that the rest is for a crotchet and a quaver. If it fits the measure, it can be used, like in your example:

But you can also use two rests, a crotchet and a quaver:

If the grouping is 3-3-3 (quavers), I think the former case is more likely to appear.