GIVEN: 2 similar cubes are placed adjacent to each other such that the total surface area of the structure is 2890 cm2 CONCEPT: Number of edges in the cube = 12 Total surface area of the structure (2 similar cubes are placed adjacent to each other) = 10 × (side) 2 Note:Total surface area of 1 cube = 6a2 .When 2 cubes are kept adjacent to each other then 2 common surfaces will come inside the structure and resultant total surface area = 6 + 6 – 2 = 10. CALCULATION:
10×(side)2=2890 ⇒(side)2=289 ⇒ Side = 17 cm Since the cube has 12 edges each equal to the side of the cube. ∴ Total length of all the edges of a cube = 17 × 12 = 204 cm