Triplicate Dual Series of Dougall--Dixon Theorem

Applying the triplicate form of the extended Gould--Hsu inverse series relations to Dougall's summation theorem for the well--poised $_7F_6$-series, we establish, from the dual series, several interesting Ramanujan--like infinite series expressions for $\pi^2$ and $\pi^{\pm1}$ with convergence rate "$-\frac{1}{27}$".