It always bothers me how whenever I am doing practice problems I never got a proper explanation as to why 5-member rings prefer(thermodynamically) being cis- rather than trans-fused( as opposed to decalins where the cis-fused rings are more stable due to gauche and 1,3-diaxial interactions). They seem to never give an explanation about the phenomenon besides "it is how it is".
I don't see an immediate reason why the cis fused would be stable. The cyclohexane would be happier having two equatorial substituents so it must have something to do with the 5-member ring.
It seems that it was to equatorial positions on the same side of the ring and next to each other( the two right-most). How do you choose which substituents to put where and where does the bulk go- I cannot see a clear factor to decide?