MathematicsMedium249×since 2002Q2383Let P(3,2,3),Q(4,6,2)\mathrm{P}(3,2,3), \mathrm{Q}(4,6,2)P(3,2,3),Q(4,6,2) and R(7,3,2)\mathrm{R}(7,3,2)R(7,3,2) be the vertices of △PQR\triangle \mathrm{PQR}△PQR. Then, the angle ∠QPR\angle \mathrm{QPR}∠QPR isAcos−1(718)\cos ^{-1}\left(\frac{7}{18}\right)cos−1(187)Bπ6\frac{\pi}{6}6πCcos−1(118)\cos ^{-1}\left(\frac{1}{18}\right)cos−1(181)Dπ3\frac{\pi}{3}3πCheck answerSkip