Can someone lend a hand with what tier sizes these might be? tia

http://blog.pinkcakebox.com/blue-bows-and-bling-wedding-cake-2010-08-24.htm

Not sure, but they look like 6", 9", 10" 12" & 14", try stacking these size pans, it may give you a better idea. HTH

A 9" square won't fit on a 10" round... it needs to go on at least a 13" round.
A 12" square won't fit on a 14" round... it needs to go on at least a 17" round.

I'd guess it's a 6" round, 7" square, 11" round, 12" square, and 18" round.

Here are the right angle measurements for squares:
4" 5.66
5" 7.07
6" 8.49
7" 9.9
8" 11.31
9" 12.73
10" 14.14
11" 15.56
12" 16.97
13" 18.38
14" 19.8
15" 21.21
16" 22.63
17" 24.04
18" 25.46

Oops