Physical Size of the Andromeda Galaxy = Length(lightyears) = θ(radians) * distance(lightyears) =3° * 2π/360° x (2 x 106 lightyears) =(0.050 radians) x (2 x 106 lightyears) = 1 x 105 lightyears = 100,000 lightyears Note: This is approximately equal to the size of the Milky Way Galaxy!

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