A line passes through A(4,-6,-2) and B(16,-2,4). The point P(a, b, c), where a, b, c are non-negative integers, on the line AB lies at a distance of 21 units, from the point A. The distance between the points P(a, b, c) and Q(4,-12,3) is equal to .
Answer
22
Solution
Direction of AB: (12, 4, 6) (6, 2, 3), |(6, 2, 3)|=7 unit vector ( 67, 27, 37 )
P=A 21 ( 67, 27, 37 )
+ sign: (4+18, -6+6, -2+9)=(22, 0, 7) ✓ non-negative; − sign gives (-14,-12,-11) ✗
PQ= 182+122+42= 484=22
Answer: 22