AP EAMCET Engineering 21 Apr 2019 Shift 2 Paper

It is given that the direction ratios of first line are 2,2,1 and the direction ratios of second line joining the points (3,1,4) and (7,2,12) are
(7−3,2−1,12−4)
(4,1,8)
The angle between the two lines is,
cos‌θ=‌

a1a2+b1b2+c1c2

√a12+b12+c12√a22+b22+c22

cos‌θ=‌

2×4+2×1+1×8

√9√81

=‌

18

27

θ=cos−1(‌

2

3

)