Question

abcd by following these steps.
the dashed line to a and c.

1. press fold to reflect the rectangle over the dashed line.
2. does the rectangle have diagonal symmetry? no
3. what is the n - fold symmetry of the rectangle? 1 2 4 check

Explanation:

Step1: Recall n - fold symmetry concept

n - fold symmetry means that an object can be rotated by $\frac{360^{\circ}}{n}$ about a central point and still look the same.

Step2: Analyze rectangle's rotational symmetry

A rectangle can be rotated by $180^{\circ}$ (i.e., $\frac{360^{\circ}}{2}$) about its center and map onto itself. It cannot be rotated by any other non - multiple of $180^{\circ}$ within the range of $0^{\circ}<\theta<360^{\circ}$ and map onto itself.

Answer:

2