= Eclipsing-binary distance
{title2=$d=R/\theta$ for angular radius $\theta$}
For a detached double-lined binary, <radial velocities> supply an orbital length scale times $\sin i$, while eclipse geometry supplies inclination and relative radii. Together they determine physical <stellar radii>. Comparing them with angular radii from a calibrated surface-brightness/colour relation gives distance. The orbital scale is geometric, but the angular-radius <calibration>, <extinction> and third light add astrophysical assumptions.<An eclipsing-binary distance to the Large Magellanic Cloud accurate to two per cent by G. Pietrzyński and others>[Nature 495, 76–79; eight late-type systems]{ref}
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