CAT 2004 — QA Question 33
Answer the following question based on the information given below.
In an examination, there are 100 questions divided into three groups A, B and C such that each group contains at least one question. Each question in group A carries 1 mark, each question in group B carries 2 marks and each question in group C carries 3 marks. It is known that the questions in group A together carry at least 60% of the total marks.
If the lengths of diagonals DF, AG and CE of the cube shown in the adjoining figure are equal to the three sides of a triangle, then the radius of the circle circumscribing that triangle will be _______.

Answer & solution
equal to the side of the cube
- B
times the side of the cube
- C
times the side of the cube
- D
impossible to find from the given information
Let the side of the cube be a units.
DF, AG and CE are body diagonals each of length a√3 units.
∴ Circumradius of the equilateral triangle = = a units
∴ Circumradius = side of cube
Hence, option (a).