Q. The number of diagonals in a polygon of $m$ sides is
A) $\frac{1}{2!}m(m - 5)$
B) $\frac{1}{2!}m(m - 1)$
C) $\frac{1}{2!}m(m - 3)$
D) $\frac{1}{2!}m(m - 2)$
Explanation
(c)
Required number of diagonals $=^{m}C_{2} - m$
$= \frac{m(m - 1)}{2!} - m$
$= \frac{m}{2!}(m - 3)$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.