18/08/2026
Class 12 || Three Dimensional Geometry Ex:-11.2 || Question no.1 Show that the three lines with direction cosines 12/13, -3/13, -4/13; 4/13, 12/13, 3/13; 3/13, -4/13, 12/13 are mutually perpendicular.
https://youtu.be/zEGYFXri1fo