Question

question 19 of 20
a ______ has two - fold rotational symmetry

a. square

b. line

c. equilateral triangle

d. circle

Explanation:

• A square has 4 - fold rotational symmetry (rotates 90° to map onto itself).
• A line has 2 - fold rotational symmetry (rotating 180° around its midpoint maps it onto itself).
• An equilateral triangle has 3 - fold rotational symmetry (rotates 120° to map onto itself).
• A circle has infinite - fold rotational symmetry.

Answer:

B. line