Sponsor Area

Three Dimensional Geometry

Question
CBSEENMA12033237

Show that the points A(2, 3, – 4), B(1, –2, 3) and C (3, 8, –11) are collinear.

Solution

The given points are A(2, 3, – 4), B(1, –2, 3), C(3, 8, –11)
The direction ratios of the AB are 1 – 2, – 2 – 3, 3 + 4 i.e. – 1 – 5,1
The direction ratios of AC are 3 – 2, 8 – 3, –11 + 4 i.e. 1, 5, – 7
∴  direction ratios of AB and AC are proportional
∴  AB is parallel to AC.
But A is a common point on both the lines.
∴   A, B, C are collinear points.