Cognitive development refers to the development of mental processes such as thinking, memory, problem-solving, and reasoning. Adolescents begin to think more systematically and logically during this stage, which is a key feature of cognitive development.
On the day of her examination, Riya sharpened her pencil from both ends as shown below. 
The diameter of the cylindrical and conical part of the pencil is 4.2 mm. If the height of each conical part is 2.8 mm and the length of the entire pencil is 105.6 mm, find the total surface area of the pencil.