What is the surface area of a rectangular prism that is 8 centimeters by 6 centimeters by 24 centimeters?

One formula for the surface area (S) of a prism is
  S = 2(LW + H(L+W))

Filling in the given values, you have
  S = 2((8 cm)·(6 cm) + (24 cm)·(8 cm + 6 cm))
  = 2(48 cm² + (24 cm)·(14 cm))
  = 2·384 cm²
  = 768 cm²

The surface area is 768 cm².

Hope i can you!