RD Sharma Class 9 solutions Chapter 20 Surface Area and volume of A Right Circular cone
Summary:
 A Right circular cone is a solid generated by revolving a line segment which passes through a fixed point and which makes a constant angle with fixed line. The fixed point is called the vertex of the cone, the fixed line is called the axis of the cone.
 For a circular cone of base radius r, slant height l and height h, we have

 Curved surface area =πrl
 Total surface area = πr(l+r)
 Volume =