a line has ___ fold rotational symmetry?

Question

A. eight-fold
B. four-fold
C. one-fold
D. two-fold

Answer 1

Based on the website below, rotational symmetry is based on how many ways you can rotate an object that would result in it looking the same way. Another way to look at is, if you rotate the object 360 degrees (a complete circle), how many times along the way does it look like it did when you started. Based on these explanations, I would say that a line has two-fold symmetry. As you rotate the line 360 degrees you will find that at 180 degrees it looks exactly the same as when you started. A vertical line, for example, looks the same upside down as it does right side up (similar to the rectangle example at this site http://www.bbc.co.uk/schools/ks3bitesize/maths/shape_and_space/symmetry_3.shtml).

Answer 2

If you rotate a line 180° about any point on the line, the line falls back on itself. How many fold is that?

Answer 3

Along which axis? you can rotate a line along its own axis as well as along the axis of any other line that intersects it at that point.

All of the above are about correct in general.