Use the formula for frustum

$V = \frac{1}{3}(A_1 + A_2 + \sqrt{A_1 \, A_2}) \, h$

$V = \frac{1}{3}(A_1 + A_2 + \sqrt{A_1 \, A_2}) \, h$

$A_1 = 4 \times 4 = 16 ~ \text{in.}^2$
$A_2 = 2 \times 2 = 4 ~ \text{in.}^2$

$h = 16(12) = 192 ~ \text{in.}$

Thus,

$V = \frac{1}{3}[ \, 16 + 4 + \sqrt{16(4)} \, ](192)$

$V = 1792 ~ \text{in.}^3$ *answer*