Find the surface area of regular prism with height 6 cm, if the base of the prism is: Regular quadrilateral with side 4 cm.

A "regular quadrilateral" is a square, so the length and width are both 4 cm. The surface area of a rectangular prism is given by
  S = 2(LW +H(L +W))
  S = 2((4 cm)*(4 cm) +(6 cm)*(4 cm +4 cm))
  S = 2(16 cm² +48 cm²)
  S = 2*64 cm² = 128 cm²

The surface area of the prism is 128 cm².