surface area

The square prism base is      4 x 4   x   5 ²          ( 5 sides)

 

Need to find the HEIGHT of the triangles

   Pythag therom    (drop a bisector from the tip the the middle of the sidelength to form a rt triangle)  )

      2 ^2 + h^2 = 6^2

        h^2 = 32

         h = sqrt 32

 

 

FOUR triangles   base = 4    height = sqrt 32     area = 1/2 b h

     4 *      1/2  4 * sqrt 32   = 8 sqrt 32 = 45.25   cm²

 

Now add the reds to finish.......