1. **Problem stated:** Find $30\%$ of $20$ and represent the result for a $20$ meter land length. 2. **Formula used:** To find a percent of a number, use $\text{part} = \frac{\text{percent}}{100} \times \text{whole}$. 3. **Substitute the values:** $$\text{part} = \frac{30}{100} \times 20$$ 4. **Simplify the fraction:** $$\frac{30}{100} = \frac{3}{10}$$ 5. **Multiply:** $$\text{part} = \frac{3}{10} \times 20$$ 6. **Cancel common factors:** $$\frac{3}{\cancel{10}} \times \cancel{20} = 3 \times 2$$ 7. **Get the answer:** $$3 \times 2 = 6$$ 8. **Final answer:** $30\%$ of $20$ is $6$. So, $30\%$ of a $20$ meter land length is $6$ meters.