Question

I need help!!! Pleasssse!!!!

Answer 1

The sum of the length and width ratio units is 6+2 = 8. Since this stands for 24 cm, each ratio unit stands for 3 cm. The actual dimensions are
  18 cm : 6 cm : 21 cm

The surface area (S) is given in terms of length (L), width (W), and height (H) by
  S = 2(LW +H(L+W))
  = 2((18 cm)*(6 cm) +(21 cm)*(18 cm +6 cm))
  = 2(108 cm² +(21 cm)*(24 cm))
  = 1224 cm²

The surface area of the box of cereal is 1224 cm².