MathematicsMedium249×since 2002Q2381Consider a △ABC\triangle A B C△ABC where A(1,3,2),B(−2,8,0)A(1,3,2), B(-2,8,0)A(1,3,2),B(−2,8,0) and C(3,6,7)C(3,6,7)C(3,6,7). If the angle bisector of ∠BAC\angle B A C∠BAC meets the line BCB CBC at DDD, then the length of the projection of the vector AD→\overrightarrow{A D}AD on the vector AC→\overrightarrow{A C}AC is :A37238\frac{37}{2 \sqrt{38}}23837B19\sqrt{19}19C39238\frac{39}{2 \sqrt{38}}23839D382\frac{\sqrt{38}}{2}238Check answerSkip