DSQ: Calculating the surface area of a cube - GMAT Quantitative Reasoning
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Ron is making a box in the shape of a cube. He needs to know how much wood he needs. Find the surface area of the box.
I) The diagonal distance across the box will be equivalent to 
.
II) Half the length of one side is 
.
Ron is making a box in the shape of a cube. He needs to know how much wood he needs. Find the surface area of the box.
I) The diagonal distance across the box will be equivalent to
II) Half the length of one side is
To find the surface area of a cube, we need the length of one side.
Statement I gives the diagonal, we can use this to find the length of one side.
Statement II gives us a clue about the length of one side; we can use that to find the full length of one side.
The following formula gives us the surface area of a cube:
Use Statement I to find the length of the side with the following formula, where 
is the diagonal and 
is the side length:
So, using Statement I, we find the surface area to be
Using Statement, we get that the length of one side is two times two:
Again, use the surface area formula to get the following:
To find the surface area of a cube, we need the length of one side.
Statement I gives the diagonal, we can use this to find the length of one side.
Statement II gives us a clue about the length of one side; we can use that to find the full length of one side.
The following formula gives us the surface area of a cube:
Use Statement I to find the length of the side with the following formula, where
So, using Statement I, we find the surface area to be
Using Statement, we get that the length of one side is two times two:
Again, use the surface area formula to get the following:
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