Tight relations between the radii of the BLR and the dust continuum. The blue circles are AGNs measured by RM, and the red diamonds are the targets measured by OI. The dashed gray lines connect the same sources with both RM and OI measured R_d. The best-fit R_BLR–R_d relations of RM and OI datasets (formula in the lower right corner of each panel) are shown as the blue and red lines, respectively. The black circles enclose the known changing-look AGNs. We only exclude Mrk 590, denoted as the empty blue circle, from our analysis. The linear scale is indicated on the top and right axes.