Correct Answer - Option 2 : 81√3 dm
3
Formula used
Diagonal of a cube = √3(side)
Given
Diagonal of a cube = 9
Calculation
√3(side) = 9
Squaring on both sides
3(side)2 = 81
⇒ (Side)2 = 27
⇒ Side = √27
⇒ Side = 3√3 dm
Volume of a cube = (3√3)3
⇒ 81√3 dm3
∴ The volume of a cube is 81√3 dm3