Given - and and they are parallel

To find – The value of m

Direction ratios of the line = (2, - m, - 3)

Direction ratios of the normal of the plane = (m, 3, 1)

Formula to be used – If (a, b, c) be the direction ratios of a line and (a’, b’, c’) be the direction ratios of the normal to the plane, then, the angle between the two is given by