Dim k As Integer
Dim i As Integer
k = 0
i = 0
 
do while a<15
 
x=a*b 'können beliebige formeln sein
z=c*d
 
ReDim Preserve array_lenght(k, i)
array_lenght(k, i) = x
i = i + 1
array_lenght(k, i) = z
k = k + 1
i = 0
 
loop
 
For k = 0 To UBound(array_lenght)
For i = 0 To UBound(array_lenght)
Print array_lenght(k, i)
Next i
Next k

umfang=2*pi*Val(text1.text) ' oder so ähnlich, 
fläche = pi*Val(Text2.text) etc.