1. **State the problem:** We need to find the length and width of a rectangle where the length is three times the width, and the perimeter is 48 cm. 2. **Recall the formula for the perimeter of a rectangle:** $$P = 2(\text{length} + \text{width})$$ 3. **Assign variables:** Let the width be $w$ cm. Then the length is $3w$ cm. 4. **Write the perimeter equation using these variables:** $$48 = 2(3w + w)$$ 5. **Simplify inside the parentheses:** $$48 = 2(4w)$$ $$48 = 8w$$ 6. **Solve for $w$:** $$w = \frac{48}{8} = 6$$ 7. **Find the length:** $$\text{length} = 3w = 3 \times 6 = 18$$ **Final answer:** Length = 18 cm Width = 6 cm