\(V_1 = 3x4x6 = 72 ~ft^3\)

\(V_2 = 3x4x(2x6) = 144 ~ft^3\)

\(\frac{V_1}{V_2} = \frac{72}{144} \)

\(V_2 = 2V_1\), the volume of the second trunk is twice the first.