1. **State the problem:** Calculate the perimeter of the first shape with sides 8cm, 8cm, 13cm, 13cm, and 9cm. 2. **Formula:** The perimeter $P$ of a polygon is the sum of the lengths of all its sides: $$P = \text{side}_1 + \text{side}_2 + \cdots + \text{side}_n$$ 3. **Apply the formula:** $$P = 8 + 8 + 13 + 13 + 9$$ 4. **Calculate step-by-step:** $$P = (8 + 8) + (13 + 13) + 9 = 16 + 26 + 9$$ 5. **Sum all values:** $$P = 16 + 26 + 9 = 42 + 9 = 51$$ 6. **Answer:** The perimeter of the shape is **51 cm**. This method applies to any polygon: add all side lengths to find the perimeter.