Let $T_n$ be the number of all possible triangles formed by joining vertices of an $n$-sided regular polygon. If $T_{n+1} - T_n = 10$, then the value of $n$ is: (1) 10 (2) 8 (3) 5 (4) 7
Let $T_n$ be the number of all possible triangles formed by joining vertices of an $n$-sided regular polygon. If $T_{n+1} - T_n = 10$, then the value of $n$ is:\\
(1) 10\\
(2) 8\\
(3) 5\\
(4) 7