An astronomer observes that a star 12.5 light-years away moves through an angle of 0.2" in 1 year. Assuming it moved in a straight line perpendicular to the initial line of observation, how many miles did the star move? (1 light-year = 5.88 ×10¹²mi.) Use Eq. (8.12).

Data from Eq. (8.12)

sinθ = tanθ = θ