Question

question 15 of 25
a has two - fold rotational symmetry.
a. equilateral triangle
b. line
c. circle
d. square

Explanation:

Step1: Recall rotational symmetry concepts

Rotational symmetry: A shape has \(n -\)fold rotational symmetry if it looks the same after a rotation of \(\frac{360^{\circ}}{n}\).

Step2: Analyze each option

• Option A (equilateral triangle):

Equilateral triangle has \(3 -\)fold rotational symmetry (\(\frac{360^{\circ}}{3}=120^{\circ}\) rotation).

• Option B (line):

A line has infinite - fold rotational symmetry (it looks the same after any rotation about its mid - point).

• Option C (circle):

A circle has infinite - fold rotational symmetry (it looks the same after any rotation).

• Option D (square):

For a square, \(\frac{360^{\circ}}{n}=180^{\circ}\) (two - fold rotational symmetry, since \(n = 2\) when rotated by \(180^{\circ}\) it maps onto itself).

Answer:

D. square