To convert pounds to kilograms using the proportion \(1 \text{ kilogram} = 2.2 \text{ pounds}\), we can set up the conversion as follows:
First, we can use the inverse of the proportion to convert pounds to kilograms:
\[ 1 \text{ pound} = \frac{1}{2.2} \text{ kilograms} \]
Now, let’s convert 72 pounds to kilograms:
\[ \text{Kilograms} = 72 \text{ pounds} \times \frac{1 \text{ kilogram}}{2.2 \text{ pounds}} = \frac{72}{2.2} \text{ kilograms} \]
Calculating that:
\[ \frac{72}{2.2} \approx 32.7272727273 \]
Rounding to the nearest tenth:
\[ 32.7 \text{ kilograms} \]
Therefore, 72 pounds is approximately 32.7 kilograms.