Given:
The length of the given prism = 6 m
The width of the given prism = 3 m
The height of the given prism = 12 m
To find the surface area of the prism.
Formula:
The surface area of the prism is

where, l be the length
b be the width
h be the height
Now,
Putting, l=6, b=3 and h=12 we get,
sq m
or,
sq m
Hence,
The surface area of the prism is 252 sq m.