Question

If ‘X’ is the order of rotation of a regular polygon with ‘n’ sides and ‘Y’ is the number of angles of rotation, what is the value of (X – Y – 1)?

• A. 1
• B. -1
• C. 0
• D. 2

Answer 1

The correct option is C

0

Order of rotation of a regular polygon with ‘n’ sides = X = n

For e.g. an equilateral triangle and a square repeat the initial position 3 and 4 times respectively for ${360}^{\circ }$ rotation.

Angles of rotation of a regular polygon with ‘n’ sides = Y = n – 1

This is because the last rotation, i.e. ${360}^{\circ }$ is not counted as angle of rotation.

So, X – Y – 1 = n – (n – 1) – 1 = n – n + 1 – 1 = 0