AP EAMCET Engineering 26 Apr 2017 Shift 1 Paper

Consider the figure shown below.The equation of line BC is,

x

2

=

y+11

8

=

z−4

−3

=λ
The coordinates of any point on the line BC are,
(2λ,8λ−11,−3λ+4)
Thus, the coordinated of D are,
(2λ,8λ−11,−3λ+4)
DR's of BC are 2,8,−3 and DR's of AD are 2λ−1,8λ−19,−3λ
Also AD is perpendicular to BC,
2(2λ−1)+8(8λ−19) +(−3)(−3λ)=0
4λ−2+64λ−152+9λ=0
77λ=154
λ=2