Three Dimensional Geometry — Maths STD 12 Science — Question
Gujarat BoardEnglish MediumSTD 12 ScienceMathsThree Dimensional Geometry5 Marks
Question
Using direction ratios show that the points A(2, 3, -4) B(1, - 2, 3) and C(3, 8, -11) are collinear.
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Answer
Here A(2, 3, -4), B(1, -2, 3) and C(3, 8, -11).
Direction ratios of AB = (1 - 2, -2 - 3, 3 + 4) = (-1, -5, 7)
Direction ratios of BC = (3 - 1, 8 + 2, -11 - 3) = (2, 10, -14)
Here, the respective direction consines of AB and AC,
$\frac{-1}{2}=\frac{-5}{10}=\frac{7}{-14}$ are proportional.
Also, Bis the common point between the two lines,
$\therefore$ The points A(2, 3, -4) B(1, -2, 3) and C(3, 8, -11) are collinear.
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