Mass-radius diagram in which KOI 74b (sky blue symbol) is represented with other white dwarfs in detached or post-common-envelope eclipsing binaries (open symbols) and noneclipsing low-mass white dwarfs (black-filled symbols). The mass ranges for KOI 74b previously calculated with ellipsoidal light variations (ELV; Rowe et al. 2010) and Doppler boosting (DB; van Kerkwijk et al. 2010) are indicated by thick dark and light gray error bars. The mass of KOI 81b is taken from van Kerkwijk et al. (2010) with an uncertainty of 20%. The mass indicated for KHWD 3 is the value obtained by Carter et al. (2010) with Doppler boosting. Procyon B (Provencal et al. 2002) and Sirius B (Barstow et al. 2005) are shown for comparison (gray-filled symbols). References for the other objects are given in the text.