Question

Let 'X' be the number of lines of symmetry and 'Y' be the order of rotational symmetry of the given figure. Then, 2X + Y + 1 = __.

• A. 10
• B. 9
• C. 12
• D. 13

Answer 1

The correct option is D 13

The figure given below has four lines of symmetry. So, X = 4.

Also, the figure needs to be rotated by an angle of ${90}^{\circ }$ to be perfectly identical to the original shape.
Therefore, the figure has to be rotated about its centre four times to get to its original position, and thus the order of rotational symmetry, Y = $\frac{{360}^{\circ }}{{90}^{\circ }}$ = 4.

Hence, 2X + Y + 1 = 13.