Answer:
Step-by-step explanation:
Look at the picture.
The formula of a Surface Area of a rectangular prism:
[tex]S.A.=2(ab+ac+bc)[/tex]
We have
[tex]a = 6\ m,\ b=3.5\ m,\ c=9\ m[/tex]
Substitute:
[tex]S.A.=2(6\cdot3.5+6\cdot9+3.5\cdot9)=213\ m^2[/tex]