11. First, we need to calculate the area of the base.
We have two 6 by 6 triangles, and one 6 by 18 rectangle. This way, the sufrace area of the base is:

To get the volume, multiply this are by the height:

Now, let's convert that into cubic centimiters:

Therefore, the volume of the described solid is:

12. The outline from the base of the solid will be some sort of "walls" when extruded those 2 m up. Now, we'll have:
• A wall that is 6m long and 2m high
,
• Two walls that are 12m long and 2m high
,
• Two walls that are 8.49m long and 2m high
,
• A wall that is 18m long and 2m high
This way, the lateral surface area, in meters, is:

Converting this into square centimiters,

We get that the lateral surface area of the solid is:
