SOLUTION: When the dimensions of a cube are reduced by 4 inches on each side, the surface area of the new cube is 864 square inches. What were the dimensions of the original cube?

Algebra ->  Surface-area -> SOLUTION: When the dimensions of a cube are reduced by 4 inches on each side, the surface area of the new cube is 864 square inches. What were the dimensions of the original cube?      Log On


   

Question 1098009: When the dimensions of a cube are reduced by 4 inches on each side, the surface area of the new cube is 864 square inches. What were the dimensions of the original cube?
Answer by ikleyn(52777) About Me  (Show Source):
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Step 1:  The area of each face of the smaller cube is  864%2F6 = 144  square inches.


Step 2:  The edge length of the smaller cube is sqrt%28144%29 = 12 inches. 


Step 3.  The edge length of the original cube is 12+4 = 16 inches.


Answer. The edge length of the original cube is 16 inches.


Solved.