In this study, we considered how four teachers reasoned about proportional situations involving geometry. We used pilot interviews conducted with in-service middle grades teachers around a set of proportional tasks. Analysis relied on a knowledge in pieces lens to uncover the resources that each teacher used in solving the tasks and which resources seemed to support the reasoning. Our findings suggest that this is an area of proportional reasoning in which multiplicative comparisons are important, but insufficient, for supporting reasoning. We also found that these teachers did not invoke the constant of proportionality in ways that supported their reasoning. [For the complete proceedings, see ED584443.]