Pythonで、decimal.getcontext().prec = 10000で多角形近似を使って、円周率を計算させてみた:
[ 0:00:00.231073 ] Count: 0 Vertices: 6 Digits after decimal point: 0
[ 0:00:24.069162 ] Count: 100 Vertices: 7605903601369376408980219232256 Digits after decimal point: 60
3.141592653589793238462643383279502884197169399375105820974944
[ 0:00:47.916064 ] Count: 200 Vertices: 9641628265553941653251772554046975615133217962696757011808256 Digits after decimal point: 120
3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117067982148086513282306647
[ 0:01:11.768749 ] Count: 300 Vertices: 12222215858006916517610674130456268966308810361995617503816842696126287798580020237100384256 Digits after decimal point: 180
3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117067982148086513282306647093844609550582231725359408128481117450284102701938521105559
