The regular nonagon has rotational symmetry of which angle measures? Check all that apply.

A regular nonagon has 9 equal sides, so its rotational symmetries occur in steps of 360° ÷ 9 = 40°. The listed angles that are multiples of 40° are 40°, 120°, 240°, and 320°; these correspond to choices A, C, D, and F.

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