Since, seven equal cubes are joined and made a cuboid. So, length of cuboid =7×5=35cm breadth of cuboid =5cm and height of cuboid =5cm Now, surface area of resulting cuboid =2(lb+bh+hl) ‌‌=2(35×5+5×5+5×35) ‌‌=2(175+25+175) ‌‌=2×375 ‌‌=750cm3