To determine the radius of the base of the cylinder, we need more context or additional information. However, if you're looking for a simple response based on the options provided, there are several potential values for the radius:
- 2
- 4
- 15
- 7.5
Each of these could be the radius of a cylinder depending on the specific situation or problem. If you can provide more details about the cylinder or the problem you are trying to solve, I'd be happy to help further!