Cis/trans with alkene substituents on cycloalkanes

My chemistry book is saying that the double bond indicated by the red arrow can generate *cis*/*trans* isomers:


[![Cis-Trans-Cyclohexene](https://i.stack.imgur.com/67VxS.png)](https://i.stack.imgur.com/67VxS.png)


I don't understand how this can be so, as you need to use *E*/*Z* priority rules in this case. If you go by the rule for *cis*/*trans* of finding the longest carbon chain containing the double bond, and seeing if the chain ends up on the opposite or same side of the bond, you find that by going around the ring, both options of *cis* or *trans* have the same length.


Am I missing something here, or is this a case where you really **should** be using *E*/*Z*, not *cis*/*trans*?


