Question

two cubes each of side 10 cm are joined end to end. Find the surface area of the resulting cuboid

Answer 1

$the \: side \: of \: the \: cube = a = 10 \: cm \\ \\ when \: joined \: end \: to \: end \: it \: forms \: a \: cuboid \\ \\ l = 20 \: cm \\ b = 10 \: cm \\ h = 10 \: cm \\ \\ surface \: area \: \\ = 2(lb + bh + hl) \\ = 2(20 \times 10 + 10 \times 10 + 10 \times 20) \\ = 2(200 + 100 + 200) \\ = 2 \times 500 \\ = 1000 \: \: cubic \: metres$