If the projections of a line segment of length “d” on the coordinate axes are d1,d2,d3respectively then d12+d22+d32=

The projection of AB on x- axis is d1=|x2−x1|The projection of AB on y- axis is d2=|y2−y1|The projection of AB on z- axis is d3=|z2−z1|Hence, d12+d22+d32=(x2−x1)2+(y2−y1)2+(z2−z1)2=d2