Multiple choice

Three solid cubes of sides 1 cm, 6 cm and 8 cm are melted to form a new cube. Find the surface area of the cube so formed.

  1. 529 sq. cm

  2. 486 sq. cm

  3. 729 sq. cm

  4. 125 sq. cm
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Volume = 1^3 + 6^3 + 8^3 = 1 + 216 + 512 = 729. Side of new cube = cube root of 729 = 9. Surface area = 6 * 9^2 = 6 * 81 = 486.

AI explanation

When the three cubes are melted, the volume of the new cube equals the sum of their volumes, calculated as 1^3 + 6^3 + 8^3 = 1 + 216 + 512 = 729 cubic cm. The side length of this new cube is the cube root of 729, which is 9 cm. The total surface area of a cube is given by the formula 6 * side^2, so the surface area is 6 * 9^2 = 6 * 81 = 486 sq. cm.

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