Answer: The surface area of a cylindrical ring is 950.4 square in.
Explanation:
We know that the surface area of an open cylinder is given by :-
, where r= radius and h= height
As per given , diameter of cylindrical ring = 6.3 in
then ,

h= 48 in
Now , the surface area of the cylindrical ring =


Hence, the surface area of a cylindrical ring is 950.4 square in.