A metal cube of edge 12m is melted to form three smaller cubes. If the edge of two smaller cubes are 6m and 8m.Find the surface area of the third smaller cube?

Evaluate: (-2/7)-4 × (-5/7)2

Volume of a cube is (sides)3= (12)3 = 1728m3
 It is melted into three other cubes ,so the volume of the cubes remains same as the volume of bigger cube .
Sides of the smaller cubes are 8m and 6m.
So the volume of the cubes is (8)3 =512m3
And volume of another cube = 63 = 216m3
So total volume = volume of cube of side 8m + volume of side 6m + remaining volume
512 + 216 + remaining volume = 1728
Remaining volume = 1000 m3
From the remaining volume a cube is formed
So the sides of the third cube is (1000)1/3= 10m
And the surface area of a cube is given by 6(sides)2
So the surface area of the third cube = 6(10)2 = 600 m2


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