What is password for sage?

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I am trying to get ready to ready to install guest additions so that I can arrange for shared folders. I have Sage running in virtual machine in an Oracle VM VirtualBox. When the VM containing Sage comes up it shows Fedora being loaded.

According to Chapter 4 Guest Additions in the Oracle VM VirtualBox User Manual, I'm told to enter yum install dkms In response I'm told "You need to be root to perform this command."

[sage@sage sage]$ sudo yum install dkms asks for a password for sage.

I have no idea what the root password is. I don't think I was asked to establish a password for root (admin)