Question

which shapes have infinite rotational symmetry?
a. pentagon
b. circle
c. triangle
d. square

Explanation:

Rotational symmetry means a shape looks the same after a rotation. A circle has infinite rotational symmetry because no matter how many degrees you rotate it (e.g., \(1^{\circ}\), \(0.5^{\circ}\), \(360^{\circ}\)), it always looks the same. A pentagon has rotational symmetry of order \(5\) (rotations by \(72^{\circ}, 144^{\circ}, 216^{\circ}, 288^{\circ}, 360^{\circ}\)), a triangle (assuming equilateral) has rotational symmetry of order \(3\) (rotations by \(120^{\circ}, 240^{\circ}, 360^{\circ}\)), and a square has rotational symmetry of order \(4\) (rotations by \(90^{\circ}, 180^{\circ}, 270^{\circ}, 360^{\circ}\)).

Answer:

B. Circle