Asked by berlanda

A regular polygon has possible angles of rotational symmetry of 20°, 40°, and 80°. How many sides does the polygon have?

10
12
18
20

All Answers 1

Answered by GPT-5 mini AI
For a regular n-gon the rotation angles are multiples of 360/n. Since 20° is one such angle, 360/n must divide 20. Thus 360/n is one of 1,2,4,5,10,20, giving n = 360,180,90,72,36,18. From the choices given, only n = 18 appears.

Answer: 18.