Create a VBA formula with a "do until" function

[TSpan]

Hello guys,

I am attempting to calculate the length and qty of horizontal lines on a triangle that are a set distance apart from the bottom. (Wall battens in the gable of a shed) I can use this formula =((Ridge-Eave)-Spacing)/TAN(RADIANS(AngleOfRoof)) but then i need to duplicate that formula this many times ROUNDDOWN((Ridge-Eave)/Spacing,0)

Can this be done in a conventional formula or will it need to be a custom VBA formula in this format?

Public Function ListItemsPrice(Quant As Range, Price As Range)
Dim Qs As New Collection, Ds As New Collection, Ps As New Collection
Dim c As Range, mTotal As Currency

For Each c In Quant
Qs.Add c
Next

For Each c In Price
Ps.Add c
Next


For i = 1 To Qs.Count
If Not Qs(i) = Empty Then
    mTotal = mTotal + (Ps(i) * Qs(i))
End If
Next i

ListItemsPrice = mTotal

'just incase selcted ranges are not equal in length
If Not Price.Count = Quant.Count Then
    ListItemsPrice = "Range Selection Error"
End If

End Function

If it has to be done in VBA what will it look like...? Im only new to it and have found the above code in a workbook i am using!

 

[TSpan]

If anyone else is looking for this i worked it out this way...

Public Function GableGirts(Height, Spacing, Angle)

Set Func = Application.WorksheetFunction
Const pi = 3.14159265358979

Gqty = Func.RoundDown(Height / Spacing, 0)
gLength = ((Height - Spacing) / Tan((Angle * pi / 180))) * 2
If Gqty < 1 Then
    gLength = 0
    Exit Function
End If
For i = 1 To Gqty
    Height = Height - Spacing
    If Height - Spacing <= 0 Then
    GableGirts = gLength
    Exit Function
    End If
    gLength = gLength + ((Height - Spacing) / Tan((Angle * pi / 180)) * 2)
Next i

GableGirts = gLength

End Function