1. **State the problem:** We have a scale drawing where 4 cm represents 9 ft. The length of the billboard in the drawing is 11 cm. We need to find the actual length of the billboard in feet. 2. **Formula and rules:** The scale ratio is given by $$\frac{\text{drawing length}}{\text{actual length}} = \frac{4}{9}$$. 3. **Set up the proportion:** Let the actual length be $x$ ft. Then, $$\frac{4}{9} = \frac{11}{x}$$ 4. **Solve for $x$:** Cross-multiply: $$4 \times x = 9 \times 11$$ $$4x = 99$$ 5. **Divide both sides by 4:** $$\cancel{4}x = \frac{99}{\cancel{4}}$$ $$x = \frac{99}{4}$$ 6. **Simplify the fraction:** $$x = 24.75$$ 7. **Interpretation:** The actual length of the billboard is 24.75 feet. **Final answer:** The actual billboard is 24.75 feet long.