To determine this you have to solve the square root of 27, else you won't know what its decimal values are:
![\sqrt[]{27}=3\sqrt[]{3}=5.196](https://img.qammunity.org/2023/formulas/mathematics/college/7si9vypp5z8zxidz2uxgwhx8107otuor5m.png)
Looking at the first three decimal values of the result, you can tell that is close to 5.2.
The dot that represents the square root of 27 is b.