Sorry, i couldnt figure out how else to post this problem than to attach the image
why is the answer not E ?[/img]
Manhattan Practice GMAT
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- aneesh.kg
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It can be derived from Pythagoras' Theorem that the length of the diagonal in a cuboid of edge lengths a,b and c is (a^2 + b^2 + c^2)^0.5.
For a cube, since all the edges are equal, the length of a diagonal for edge length 'a' is a(3)^0.5.
So, for a edge length 10, the length of the diagonal is 10(3)^0.5.
If you draw a cube with a sphere completely inscribed in it, you will see that the diameter of the sphere = edge of the cube and
The Shortest possible distance from one vertex to surface of sphere = Half of (length of diagonal - diameter of spehere)
= 1/2*(10(3)^0.5 - 10)
= 5(3)^0.5 - 5
(D) is the answer
For a cube, since all the edges are equal, the length of a diagonal for edge length 'a' is a(3)^0.5.
So, for a edge length 10, the length of the diagonal is 10(3)^0.5.
If you draw a cube with a sphere completely inscribed in it, you will see that the diameter of the sphere = edge of the cube and
The Shortest possible distance from one vertex to surface of sphere = Half of (length of diagonal - diameter of spehere)
= 1/2*(10(3)^0.5 - 10)
= 5(3)^0.5 - 5
(D) is the answer
Aneesh Bangia
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Thanks Aneesh,
I now realized my mistake,
i was trying to visualize a two dimensional figure and was calculating the distance of the vertex to the surface of the "circle" and not the sphere
I now realized my mistake,
i was trying to visualize a two dimensional figure and was calculating the distance of the vertex to the surface of the "circle" and not the sphere
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Yes I have understood now as to what mistakes I was committing:
The longest diagonal in a Cube is l x root 3.
So the correct answer as D is the perfect answer...
The longest diagonal in a Cube is l x root 3.
So the correct answer as D is the perfect answer...
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LEARNING, APPLICATION AND TIMING IS THE FACT OF GMAT AND LIFE AS WELL... KEEP PLAYING!!!
Whenever you feel that my post really helped you to learn something new, please press on the 'THANK' button.