1. The problem is to find the total surface area of a trapezoidal prism with given dimensions. 2. The formula for the surface area of a prism is the sum of the areas of all its faces. 3. You calculated the areas of three pairs of faces: - Sides (2 faces): $a = l \times w \times 2 = 10 \times 11.5 \times 2 = 230$ cm² (Note: your calculation says 350 cm², which seems incorrect) - Front/Back (2 faces): $a = l \times w \times 2 = 17.5 \times 6 \times 2 = 210$ cm² (correct) - Top/Bottom (2 faces): $a = b \times \frac{h}{2} \times 2 = 10 \times 6 \times 2 / 2 = 60$ cm² (correct) 4. Let's verify the side area calculation: $10 \times 11.5 = 115$ $115 \times 2 = 230$ cm², not 350 cm². 5. Now, sum all areas: $$230 + 210 + 60 = 500 \text{ cm}^2$$ 6. Your total surface area should be approximately 500 cm², not 620 cm². 7. Therefore, your answer is not correct due to the error in the side area calculation. Final answer: Total surface area $= 500$ cm².