Ex 11.2, 3 - Show line (4, 7, 8), (2, 3, 4) is parallel to - Angle between two lines - Direction ratios or cosines

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  1. Chapter 11 Class 12 Three Dimensional Geometry
  2. Serial order wise

Transcript

Ex 11.2, 3 Show that the line through the points (4, 7, 8), (2, 3, 4) is parallel to the line through the points ( 1, 2, 1), (1, 2, 5). Two lines having direction ratios 1, b1, c1 and 2, b2, c2 are parallel if = = Also, a line passing through (x1, y1, z1) and (x2, y2, z2) has the direction ratios (x2 x1), (y2 y1), (z2 z1) Now, 1 2 = 2 2 = 1, 1 2 = 4 4 = 1 1 2 = 4 4 = 1 Since 1 2 = 1 2 = 1 2 = 1, Therefore, the given lines are parallel.

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