Calculate the surface area of a tiger nut given its length, width, and thickness using the provided formula.

The length, width, and thickness of the tiger nut are:
$L = 39.62 \text{ mm}$
$W = 17.62 \text{ mm}$
$T = 18.69 \text{ mm}$

The given formula is:

This can also be written using square roots:

$W \cdot T = 17.62 \times 18.69 = 329.2198 \text{ mm}^2$
$L \cdot T = 39.62 \times 18.69 = 740.5798 \text{ mm}^2$
$L \cdot W = 39.62 \times 17.62 = 697.9844 \text{ mm}^2$

$\sqrt{W \cdot T} = \sqrt{329.2198} \approx 18.14441 \text{ mm}$
$\sqrt{L \cdot T} = \sqrt{740.5798} \approx 27.21360 \text{ mm}$
$\sqrt{L \cdot W} = \sqrt{697.9844} \approx 26.41940 \text{ mm}$

$18.14441 + 27.21360 + 26.41940 = 71.77741 \text{ mm}$

$S = \pi \times 71.77741 \text{ mm}$
$S \approx 3.1415926535 \times 71.77741 \text{ mm}$
$S \approx 225.52909 \text{ mm}^2$

$S \approx 225.53 \text{ mm}^2$

The surface area of the tiger nut is: