C.31.25cm^2 To work out the area of the square(the bottom of pyramid) you square 2.5 which is 6.25 Then you work out the area of a triangle- 2.5*5/2=6.25 Times 6.25 by 4 because it is a square based pyramid =25 Then add the square and triangles together 25+6.25=31.25cm
