To divide by a fraction, you can multiply by its reciprocal. So, to calculate \( 72 \div \frac{1}{3} \), you can multiply 72 by the reciprocal of \( \frac{1}{3} \), which is 3.
So,
\[ 72 \div \frac{1}{3} = 72 \times 3 = 216 \]
Therefore, \( 72 \div \frac{1}{3} = 216 \).