Unless I'm doing something wrong there seems to be no value output and the vector output doesn't work as a substitute.
Hi realjayjobes; that is an excellent question!
There is no longer a Value output for the Vector Math > Cross Product, because the cross product of two vectors always results in a vector. The value of a vector is not defined and in the old Blender it was a mathematical crime to even have a value output. You might suspect the value to be the length of the vector, but it was not.
To get the desired result in modern Blender, you need a Vector Math node set to Distance.
Ahh I see - the value socket is now gone. Makes sense how you solved it spikeyxxx. In the voice of Ian Malcom: "Spikey, uh, finds a way."