document.write( "Question 717718: determine the length of one edge of a cube that has a surface area of 864 square inches \n" ); document.write( "

Algebra.Com's Answer #440446 by jsmallt9(3758) $\"\"$ $\"About$

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The surfaces/faces of a cube are squares. There are six identical square faces on a cube. The \"length of one edge of the cube\" will be the length of a side of one of the square faces. If we call the length of the side of a square \"s\", then the area of one square face will be: $\"s%5E2\"$ . The area of all six square faces will be: $\"6s%5E2\"$ . We are told that the total surface area is 864 square inches. So:
\n" ); document.write( " $\"6s%5E2+=+864\"$
\n" ); document.write( "Now we solve for s. Dividing by 6:
\n" ); document.write( " $\"s%5E2+=+144\"$
\n" ); document.write( "Find the square root of each side. When finding the square root of each side you should either remember the negative square root or have a specific reason for ignoring it! Since s is the a length and lengths aren't negative, we can ignore the negative square root.:
\n" ); document.write( " $\"s+=+12\"$
\n" ); document.write( "So the length of one edge of the cube is 12 inches. \n" ); document.write( "

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