3. Rotations
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Rotational symmetry means that you can spin the figure 180^(∘) or less so that it maps onto itself.
F
Consider the given regular polygon.
Notice that if we draw a circle in the middle of the triangle we obtain three congruent angles.
Since a circle is 360^(∘), we know that the measure of each angle is equal to 120^(∘). 360^(∘)/3=120^(∘) Then, if we rotate the triangle by 120^(∘), it will map onto itself.
This means that the given triangle has a rotational symmetry, and rotations of 120^(∘) map it onto itself. Therefore, the correct option F.