Total surface area of a cube is 486 sq cm, find sum of length of all its edges?
Let the side of the cube = $$a$$ cm
Total surface area of cube = $$6a^2 = 486$$
=> $$a^2 = \frac{486}{6} = 81$$
=> $$a = \sqrt{81}=9$$ cm
Number of edges in a cube = 12
$$\therefore$$ Sum of all edges = $$12 \times 9 = 108$$ cm
=> Ans - (B)
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