Comparison between the WD radii predicted by Eq. (2) and those of the WDs in the ZTF DWD dataset with both mass and radius listed. The black points represent the observed WDs, with measurement uncertainties. The blue line shows the radii as predicted by Eq. (2), and the orange line shows those radii multiplied by 3/2. The two outliers with the largest radii might be extremely low-mass WDs (Burdge et al. 2020b), or could be hot subdwarfs instead of WDs (Kosakowski et al. 2023b; Lin et al. 2024; Rebassa-Mansergas et al. 2024).