To convert pounds to kilograms using the given proportion (1 kilogram = 2.2 pounds), you can set up the equation:
\[ \text{kilograms} = \frac{\text{pounds}}{2.2} \]
For 72 pounds:
\[ \text{kilograms} = \frac{72}{2.2} \approx 32.7272727273 \]
Rounding to the nearest tenth:
\[ 32.7 \text{ kilograms} \]
So, the correct response is 32.7.