I think your missing the point There is no data on the extended partition. Think of it this way, you have a cup cake pan that can hold 12 cup cakes. the 12 cup cakes are the partitions and the pan is the "extended" or container that holds the partitions.
What is the FS of that partition? Not the extended
What is the output of
Code:
su - (to become root don't forget the dash )
fdisk -l