Make sure in the first case, the t-butyl group and the ethyl group are cis to each other and the vinyl group is trans to these two groups. "There are two stereoisomers of1-t-butyl-3-ethyl-5-vinylcyclohexane (a vinyl group isCH2=CH-). Make sure your second isomer has the t-butyl group and the vinyl group cis to each other and the ethyl group trans to these two groups. Which of these structures is more stable?"