What is the E/Z configuration of cyclic compounds? What are the configurations of 1-bromo-3-methylcyclopent-1-ene and 1-nitro-2-(propan-2-yl)benzene? Are they E or Z? Are they cis or trans?




What are the rules for these types of isomerism?
What is the meaning of cis and trans?
cis means on the same side (or face), trans means on the opposite side (or face).
Can I use cis and trans for cylic compounds?
Yes, you can describe the relative orientation of substituents on a ring using cis and trans, such as in the case of 1,3-dibromcyclohexane.

Can I use cis and trans for alkenes?
Yes, in priciple. But you should rather use E and Z. Note that these descriptors are taken from German.

E means entgegen and refers to opposite directions (or sites), while Z means zusammen, which is together, that is the same direction (or site).
What about the compounds in my question?
E/Z or cis/trans are not applicable here.
In the first case, the $\ce{Br}$ atom is in the ring plane, the methyl group can be above or below it. You could describe the absolute stereochemistry at the centre bearing the $\ce{CH3}$ substituent using R or S.
In the second case, there's no alkene at all but a disubstituted benzene. The relative orientation of the substituents on these systems can be described by assigning the proper numbers or by using the ortho- meta- or para-prefix. For this compounds, 2-isopropylnitrobenzene or o-isopropylnitrobenzene would be ok.