I am obliged to confess that the australian aboriginal's command of mathmatics was indeed a fairly minimal affair: a binary system that distinguished only between one, and more than one- eg;
Wagga, meaning crows, when repeated as in Wagga Wagga, means place of many crows[ an australian city ]. A similar system is used to distinguish size: Murrum, meaning water, becomes Murrumbidgee to denote 'little water[ a river that runs through that same town ].
The concept of 'pi' as in greek mathmatics would I imagine, have been recieved with more amusement than serious interest by the australian aboriginal- but then 'pyramid building' was never very high on their agenda[ I mean what the heck, they could bring down a running kangaroo at 150 metres with that boomerang they later exported to the ancient egyptians]
ps: I will fully understand if you find this humble offering unworthy of further response.