The file format can typically be identified by its file extension, which appears after the last dot in the file name. It indicates the type of file and determines which program should be used to open it. For example:
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.