Hello Kafka presenting a better question (this is not the question, agent spooner..) quite always bring you better answers. Otherway you can reread carefully the docs of Tk geometry manager, or search the monastery or the web for examples. I have done only few things wit Tk but i created many positioned windows (maybe i miss your question, btw) in my Tartaglia's triangle fun.
Search for construction of the triangle windows in the

sub draw_triangle {

   ..

   $tart_win->geometry("300x450+708+0");
[download]

HtH
L*