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Let ABCD be a tetrahedron such that the edges AB, AC and AD are mutually perpendicular. Let the areas of the triangles ABC, ACD and ADB be 5, 6 and 7 square units respectively. Then the area (in square units) of the Δ BCD is equal to :

1. 110
2. 7 3
3. 340
4. 12

Correct answer: 110

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