Rotate GameObject by pivot

Hello everyone.
I'm trying to rotate a certain GameObject that has it's center in the lower left corner. I need to rotate it by a center calculated on runtime. The rotation is made by using direction vectors but I can't find any method in the Unity API that seems to rotate a GameObject by a certain pivot using vectors as source of direction change.
Does anybody knows how to help me?

 

One approach:

- Create a new GameObject at the desired pivot point
- Parent the object you want rotated to this GameObject
- Rotate the root GameObject however much you want
- Unparent the object in question
- Destroy the original root GameObject.

Alternately if you want to do it pure-math, the steps are as follows:

- subtract the pivot position from your object
- rotate your object
- add the pivot position back into your object

 

I solved by implementing your first suggestion, thank you very much