Other things remain the same.

Reduced surface area =2 decimeters * bottom circumference

So the circumference of the bottom is equal to 25. 12/2= 12.56 decimeter.

Calculation radius 2r= 12.56/3. 14.

R=2 decimeters

Steel: 2 square *3. 14* 10 decimeter = 125.6 cubic decimeter.