Find the sum of the lengths of all edges and the surface area of the cube if its edge is 7 cm.
| March 11, 2021 | education
To calculate the surface area of a cube, we use the formula S = 6a ^ 2. By the condition of the problem, the edge of the cube is 7 cm. Substitute this value into the formula. We get: S = 6a ^ 2 = 6 * 7 ^ 2 = 6 * 49 = 294 cm ^ 2.
A cube has 12 edges, therefore, in order to find out the sum of the lengths of all its edges, it is enough to multiply 12 by the length of one edge, according to the problem statement, this is 7 cm.We get 12 * 7 = 84 cm.
Answer: S = 294 cm ^ 2; 84 cm is the sum of the lengths of all the edges of the cube.
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