Triangular Numbers.....Part-2

Let $t_{n}$ denote the $n^{th}$ triangular number. Let $t_{a},t_{b},t_{c}$ be three successive triangular numbers such that their sum is perfect square.Find the minimum possible value of $a+b+c$ .

Note- A triangular number is a number in the form of $\frac{n(n+1)}{2}$ where $n\ge1$ .