1. **State the problem:** We need to find the percentage increase in the price of a sofa that was originally 540 and increased by 135. 2. **Formula for percentage increase:** $$\text{Percentage Increase} = \left(\frac{\text{Increase}}{\text{Original Price}}\right) \times 100$$ 3. **Substitute the values:** $$\frac{135}{540} \times 100$$ 4. **Simplify the fraction:** $$\frac{135}{540} = \frac{135 \div 27}{540 \div 27} = \frac{5}{20}$$ 5. **Further simplify:** $$\frac{5}{20} = \frac{\cancel{5}}{\cancel{20}} = \frac{1}{4}$$ 6. **Calculate the percentage:** $$\frac{1}{4} \times 100 = 25$$ 7. **Answer:** The percentage increase in the price of the sofa is **25%**.