Answer:
[tex]\large\boxed{Surface\ Area=63\ cm^2}[/tex]
Step-by-step explanation:
We have
square with sides s = 3cm
four triangles with base b = 3cm and height h = 9cm.
The formula of an area of a square:
[tex]A_\square=s^2[/tex]
The formula of an area of a triangle:
[tex]A_\triangle=\dfrac{bh}{2}[/tex]
Substitute:
[tex]A_\square=3^2=9\ cm^2\\\\A_\triangle=\dfrac{(3)(9)}{2}=\dfrac{27}{2}=13.5\ cm^2[/tex]
The Surface Area:
[tex]S.A.=A_\square+4A_\triangle\\\\S.A.=9+4(13.5)=9+54=63\ cm^2[/tex]
