Consider the molecule 1-tert-butyl-3-methylcyclohexane. These two groups can be cis or trans. Which arrangement is more stable

Cis configuration is more stable

Explanation:

Generally the is configuration of cycloalkenes is more thermo-chemically stable than the trans-configuration  double bonds, because the latter causes twists in the ring, resulting in higher strain.

This also mean that there is a greater force of repulsion between cis molecules (little r no twists).

I hope you find this explanation was clear and helpful.

they are all solids.