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GATE 2014 CS (CS1) – Question 10

General Aptitude · Spatial Aptitude: Spatial Reasoning and Visualization · 2 marks · Numerical answer

An interior point of a tetrahedron (a solid with four triangular faces) is connected to its corners by straight lines. How many new internal planes are created by these lines?

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Correct answer: 6 to 6

Explanation

Any pair of the four vertex-joining lines determines a plane through the interior point and the corresponding edge. There are C(4,2)=**6** such planes. They are distinct because an interior point is not on any face plane containing three vertices.