Giải thích các bước giải:

Ta có:

 $\begin{aligned}
& \widehat{MON} = (OA, ON) - (OA, OM) \\
& \widehat{MON} = \dfrac{7\pi}{6} - \dfrac{\pi}{2} \\
& \widehat{MON} = \dfrac{2\pi}{3} \\
& \widehat{MOP} = (OA, OM) - (OA, OP) \\
& \widehat{MOP} = \dfrac{\pi}{2} - \left(-\dfrac{\pi}{6}\right) \\
& \widehat{MOP} = \dfrac{2\pi}{3} \\
& \widehat{NOP} = 2\pi - \left(\widehat{MON} + \widehat{MOP}\right) \\
& \widehat{NOP} = 2\pi - \left(\dfrac{2\pi}{3} + \dfrac{2\pi}{3}\right) \\
& \widehat{NOP} = \dfrac{2\pi}{3} \\
& \widehat{MON} = \widehat{MOP} = \widehat{NOP} = \dfrac{2\pi}{3} \\
& MN = NP = PM \\
& \text{Kết luận: Tam giác MNP là tam giác đều}
\end{aligned}$