मराठी

Prove that the Tetrahedron with Vertices at the Points O(0, 0, 0), A(0, 1, 1), B(1, 0, 1) and C(1, 1, 0) is a Regular One.

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प्रश्न

Prove that the tetrahedron with vertices at the points O(0, 0, 0), A(0, 1, 1), B(1, 0, 1) and C(1, 1, 0) is a regular one.

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उत्तर

The faces of a regular tetrahedron are equilateral triangles.
Let us consider\[\bigtriangleup\]

\[OA = \sqrt{\left( 0 - 0 \right)^2 + \left( 0 - 1 \right)^2 + \left( 0 - 1 \right)^2}\]
\[ = \sqrt{2}\]

\[OB = \sqrt{\left( 1 - 0 \right)^2 + \left( 0 - 0 \right)^2 + \left( 1 - 0 \right)^2}\]
\[ = \sqrt{2}\]
\[AB = \sqrt{\left( 1 - 0 \right)^2 + \left( 0 - 1 \right)^2 + \left( 1 - 1 \right)^2}\]
\[ = \sqrt{2}\]
Hence, this face is an equilateral triangle.
Similarly,\[\bigtriangleup\]OBC,\[\bigtriangleup\]OAC,
\[\bigtriangleup\] ABC all are equilateral triangles.

Hence, the tetrahedron is a regular one.

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पाठ 28: Introduction to three dimensional coordinate geometry - Exercise 28.2 [पृष्ठ १०]

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आर.डी. शर्मा Mathematics [English] Class 11
पाठ 28 Introduction to three dimensional coordinate geometry
Exercise 28.2 | Q 13 | पृष्ठ १०

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