The anagen phase, or the growth phase, is the first stage of the hair growth cycle. During this phase, hair actively grows as cells in the hair follicle divide rapidly, adding length. It lasts 2–7 years, varying by genetics and body region. Approximately 85–90% of scalp hairs are in this phase at any time. The longer the anagen phase, the longer the hair grows.
Example : Imagine a sprouting plant where the root actively absorbs nutrients, promoting continuous growth upward.
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.