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Mathematics - 3D Coordinate Geometry Question with Solution | TestHub

Mathematics3D Coordinate GeometryAngle between two planesMedium2 minQB

MathematicsMediumsingle choice

A tetrahedron has vertices at $O (0, 0, 0), A (1, 2, 1), B (2, 1, 3)$ and $C (- 1, 1, 2)$ . Then the angle between the faces OAB and ABC will be

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Answer:

Solution:

Normal to face OAB is $O A \times OB = (5, - 1, - 3)$ . Normal to face ABC is $A B \times A C = (1, - 1, 2) \times (- 2, - 1, 1) = (1, - 5, - 3) . cos θ = \frac{5 + 5 + 9}{35} = \frac{19}{35} .$

Stream:JEESubject:MathematicsTopic:3D Coordinate GeometrySubtopic:Angle between two planes

⏱ 2mℹ️ Source: QB

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