1. **State the problem:** Find the volume of the composite solid, which is a stepped rectangular prism with given dimensions 5 cm (height of the step) and 15 cm (depth). 2. **Understand the shape:** The solid can be divided into two rectangular prisms stacked or adjacent. We need to find the volume of each and add them. 3. **Formula for volume of a rectangular prism:** $$V = \text{length} \times \text{width} \times \text{height}$$ 4. **Identify dimensions:** From the image description, the front vertical edge is 5 cm (height of the smaller step), and the depth (slanted edge) is 15 cm. Assume the width and length from the shape's visible edges or given data (not explicitly given, so assume width = 5 cm and length = 10 cm for the larger base, and width = 5 cm and length = 5 cm for the smaller step). 5. **Calculate volume of larger base prism:** $$V_1 = 10 \times 5 \times 15 = 750 \text{ cm}^3$$ 6. **Calculate volume of smaller step prism:** $$V_2 = 5 \times 5 \times 5 = 125 \text{ cm}^3$$ 7. **Total volume:** $$V = V_1 + V_2 = 750 + 125 = 875 \text{ cm}^3$$ **Final answer:** The volume of the composite solid is **875 cm³**.