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# Show that the Line Joining the Origin to the Point (2, 1, 1) is Perpendicular to the Line Determined by the Points (3, 5, – 1), (4, 3, – 1). - CBSE (Science) Class 12 - Mathematics

#### Question

Show that the line joining the origin to the point (2, 1, 1) is perpendicular to the line determined by the points (3, 5, – 1), (4, 3, – 1).

#### Solution

Let OA be the line joining the origin, O (0, 0, 0), and the point, A (2, 1, 1).

Also, let BC be the line joining the points, B (3, 5, −1) and C (4, 3, −1).

The direction ratios of OA are 2, 1, and 1 and of BC are (4 − 3) = 1, (3 − 5) = −2, and (−1 + 1) = 0

OA is perpendicular to BC, if a1a2 + b1b2 + c1c2 = 0

∴ a1a2 + b1b2 + c1c2 = 2 × 1 + 1 (−2) + 1 ×0 = 2 − 2 = 0

Thus, OA is perpendicular to BC.

Is there an error in this question or solution?

#### APPEARS IN

NCERT Solution for Mathematics Textbook for Class 12 (2018 to Current)
Chapter 11: Three Dimensional Geometry
Q: 1 | Page no. 497

#### Video TutorialsVIEW ALL [4]

Solution Show that the Line Joining the Origin to the Point (2, 1, 1) is Perpendicular to the Line Determined by the Points (3, 5, – 1), (4, 3, – 1). Concept: Equation of a Line in Space.
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