Question 75941
In the first cube each face has sides of 2x. The area of each face is the product of two
sides. Therefore, the area of a single face on this cube is 2x * 2x = 4x^2.  But there
are 6 faces on a cube (4 faces around plus top and bottom).  So to get the entire surface area
you need to multiply the area of one face time 6 faces.  When you do that you find that:
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4x^2 * 6 = 24*x^2.
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For this particular cube you can use as the equation for surface area (S) and having as
the length L of a side a measure of 2x:
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S = 6*L*L = 6*L^2 =6*(2x)^2 = 6*4x^2 = 24x^2
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The second cube will also have a surface area of:
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S = 6*L*L = 6*L^2
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but this time L = 4x.  If you substitute 4x for L you get:
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S = 6*(4x)^2 = 6*16x^2 = 96x^2
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Note that this area is 4 times the surface area of the first cube.
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Hope this helps you to understand the problem a little more.