Thank you for the opportunity to help you with your question!

A cone is a three - dimensional geometric figure that tapers smoothly from a flat base (frequently, though not
necessarily, circular) to a point called the apexor vertex.

It has one bace and one lateral face

Cross section parallel to base has the same shape, as bace (circular)

Cross section perpendicular to base is triangle

Еo find the total surface area of the cone , we
must find the area of the side surface (lateral face) and the base.

Formula of cone side surface (Ssf) is Ssf= pi*r*l where cone.JPG

Formula of cone base (Sb) is Sb= pi*r^2

Formula of total surface area(St) is St= Ssf+Sb

Formula of cone volume is Vc= 1/3 *pi*r^2*H where h is height of cone

Please let me know if you need any clarification. I'm always happy to answer your questions.