1. **State the problem:** Anwar built a square deck with an area of 256 square feet. He wants to build a railing on three sides of the deck. We need to find the total length of the railing. 2. **Formula and rules:** The area of a square is given by $$\text{Area} = \text{side}^2$$. To find the side length, take the square root of the area. 3. **Calculate the side length:** $$\text{side} = \sqrt{256} = 16 \text{ feet}$$ 4. **Calculate the total length of railing on three sides:** Since each side is 16 feet, railing on three sides is: $$3 \times 16 = 48 \text{ feet}$$ 5. **Answer:** The total length of the railing needed is **48 feet**.