The ratio of the total surface areas of two cubes is 49 : 81. What is the ratio of their volumes?
Answer & explanation
Correct answer: option 1
The ratio of the total surface areas of two cubes = 49 : 81
Then the ratio of their sides = \(\sqrt {49}\) : \(\sqrt {81}\) = 7 : 9
Now, the ratio of their volume = 72 : 92 = 343 : 729