Hi,
no error handling included, no check for more than one selected area or more than one column:
Dim lngCounter As Long
Dim lngRowCount As Long
Dim rngTriang As Range
Set rngTriang = Selection
lngRowCount = rngTriang.Row
For lngCounter = Selection.Rows.Count To 1 Step -1
Set rngTriang = Union(rngTriang, Range(Cells(lngRowCount, Selection.Column), Cells(lngRowCount, Selection.Column + lngCounter - 1)))
lngRowCount = lngRowCount + 1
Next lngCounter
rngTriang.Select
Set rngTriang = Nothing
Ciao,
Holger