890 μm integrated flux (normalized to a common distance of 150 pc) as a function of exponential cut-off radius, constrained by fitting spatially resolved observations with angular resolution better than 0.75′′. For some disks, the 890 μm flux was extrapolated from the measured 1.3 mm flux assuming an average spectral index α = 3.0. Yellow elements are Taurus-Auriga and Ophiuchus disks from the Andrews (2015) compilation; blue elements are Lupus disks analyzed in this paper. Gray lines represent the correlations found by the Bayesian linear regression for the Taurus-Auriga and Ophiuchus disks (dash-dotted), for the Lupus disks (dashed), and for both the samples taken together (solid).