A line has direction ratios (1, 1, 2) and meets the plane x - y + z = 0. The angle ϕ between them satisfies

1. Direction vector b = (1, 1, 2); plane normal n = (1, -1, 1). 2. Dot product b · n = 1 - 1 + 2 = 2. 3. Magnitudes |b| = √6, |n| = √3. 4. sin ϕ = (b · n) / (|b| |n|) = 2/(√6 · √3) = 2/√18. _Source: NCERT Class 12 Maths Part 2 Ch 11 "Three Dimensional Geometry", §11.10_