A single rectangle has the area of (11 mm)(8 mm) = 88 mm² So the lateral areas which are the total number of rectangles will be 6*(88 mm²) = 528 mm² Just recall the formula of the regular polygon, given the side of that polygon. This hexagon has the area of (1/4)*(6)*(8²)*cot(180°/6) = 166.28 mm² There are two bases; so 2*(166.28 mm²) = 332.55 mm²
Hence, the surface area is lateral areas + base areas: 528 mm² + 332.55 mm² = 860.55 mm² (ANSWER: d)
