Magic Constant of Order 5 Magic Square/Proof 2

Theorem

The magic constant of the order $5$ magic square is $65$.

Proof

Let $M_n$ denote the magic square of order $n$.

By Magic Constant of Magic Square, the magic constant of $M_n$ is given by:

$S_n = \dfrac {n \left({n^2 + 1}\right)} 2$

Setting $n = 5$:

$S_5 = \dfrac {5 \times 26} 2 = 65$

$\blacksquare$