resize() in QDialog

Hi

My Application have 3 pages. 1st Page is QMainWindow, 2nd Page is QDialog, 3rd Page is QDialog. All three Pages are resizable upto Minimum Size to Maximum Size.

When I Expand First Page to (900,700) and Click to go next Page, Next page will show of the same width and height, I used
resize(PreviousPage->width(), PreviousPage->height);
updateGeometry();

But problem is that When I click on the Maximize Button, it will not come as minimum size. It starts resizing from PreviousPage->width() and PreviousPage->height.

I want that It should show as PreviousPage->width() and PreviousPage->height (900,700)
but its minimum size should be(850,600) and Maximum Size should be (16777215,16777215)

Kindly tell me which function will be use.

Thanks
Santosh