  Using VLTI/VINCI angular diameter measurements, we constrain the evolutionary
status of three asteroseismic targets: the stars $\delta$ Eri, $\xi$ Hya,
$\eta$ Boo. Our predictions of the mean large frequency spacing of these stars
are in agreement with published observational estimations. Looking without
success for a companion of $\delta$ Eri we doubt on its classification as an RS
CVn star.
