I just did one of these. I guessed that normal form is
[tex]x \cos \phi + y \sin \phi - p = 0[/tex]
Here' that's
[tex] x (\sqrt{3}/2) + y (1/2) - 10 = 0 [/tex]
[tex] \sqrt{3} x + y - 20 = 0[/tex]
Choice b
