Answer:
120 cm²
Explanation:
Since there are 7 cubes and the total volume = 56 cm³, each cube must have a volume of 56/7 = 8cm³ since the cubes are identical
The volume of a cube of side a = a³
Therefore a³ = 8
a=∛8 = 2
So each cube has a side length of 2 cm
To calculate the surface area note that each cube presents only 5 of its faces to the outside world. The sixth face is hidden inside the block. Also out of the 7 cubes, one cube is completely enclosed and none of its faces contribute to the total surface area. So we take only 6 cubes total into consideration for computing surface area
The face area of each cube = a² = 2² = 4
So surface area of each cube = 4 x 5 = 20 cm²
Surface are of 6 cubes = 20 x 6 = 120 cm²