1. **State the problem:** We have a small unshaded rectangle measuring 2 cm by 1 cm. Two copies of this rectangle are joined side by side horizontally to form a larger shaded rectangle. We need to find the perimeter of this larger shaded rectangle. 2. **Identify dimensions of the larger rectangle:** Since two rectangles of width 2 cm each are joined side by side, the total width is: $$2 + 2 = 4\text{ cm}$$ The height remains the same as the smaller rectangle, which is 1 cm. 3. **Recall the perimeter formula for a rectangle:** $$\text{Perimeter} = 2 \times (\text{width} + \text{height})$$ 4. **Calculate the perimeter:** $$\text{Perimeter} = 2 \times (4 + 1) = 2 \times 5 = 10\text{ cm}$$ 5. **Final answer:** The perimeter of the larger shaded rectangle is **10 cm**.