# Angle between two intersecting lines

**Geometry**Level 2

Let \(l \) be the line that is perpendicular to the \(xy\)-plane and passes through the point \( (2, 1, -3). \) Let \(m\) be the line that is perpendicular to the \(x\)-axis and passes through the same point \( (2, 1, -3). \) Find the value of \( \cos {\theta} ,\) where \( \theta \) is the acute angle between \(l\) and \(m.\)