The GATE Grind

GATE 2024 ME – Question 10

General Aptitude · Spatial Aptitude: Spatial Reasoning and Visualization · 2 marks · Multiple choice

Four equilateral triangles are used to form a regular closed three-dimensional object by joining along the edges. The angle between any two faces is

  1. 30°
  2. 60°
  3. 45°
  4. 90°

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Show answer and explanation

Correct answer: (B) 60°

Explanation

Four equilateral triangles joined along their edges form a regular tetrahedron. Every face is an equilateral triangle, and at each vertex the angle that two faces make along a shared edge in the flat triangle is 60°, so 60° is the only option that fits the shape.