\"\"

\

Let \"\" represent interior angle of a regular 30-gon.

\

\"\"                (Apply interior angle formula)

\

\"\"              (Substitute \"\" in above formula)

\

\"\"                    (Subtract: \"\")

\

\"\"                          (Multiply: \"\")

\

\"\"                               (Divide: \"\")\"\"

\

Since 168 is not a factor of 360,a 30-gon will not tessellate the plane.