The distance of the point ( 3, 4, 5) from X- axis is
let L be the foot of perpendicular from the point ( 3, 4, 5) to X axis ,then coordinate of L will be (3,0,0) [ because on X axis y and z coordinate are zero]
then distance of the point ( 3, 4, 5) from X- axis i.e. from L (3,0,0) is given by =