To draw cis-1,2-dimethylcyclohexane in its more stable chair conformation, start by sketching the chair form of cyclohexane. In this chair conformation, you should place the two methyl groups on adjacent carbon atoms (1 and 2 positions) since the compound is specified as ‘cis.’
In the chair conformation, one of the most stable arrangements occurs when substituents that are less sterically hindered are placed in the equatorial position. In the case of cis-1,2-dimethylcyclohexane, both methyl groups will prefer the equatorial positions to minimize steric strain and enhance stability.
When both methyl groups are in equatorial positions, they experience minimal interactions with other hydrogen atoms on the cyclohexane ring, resulting in a more stable configuration.
To summarize, in the more stable chair conformation of cis-1,2-dimethylcyclohexane, both methyl groups are equatorial.