The document discusses calculating the surface area of a cone. It states that the surface area is equal to the area of the circular base plus the area of the lateral surface. The area of the circular base is πr^2 and the area of the lateral surface is πrl, so the total surface area of a cone is πr^2 + πrl.

1. Surface area of cone

2. Surface area of cone

3. Area of a circle having sector (circumference) 2 π l = π l 2 Area of circle having circumference 1 = π l 2 / 2 π l So area of sector having sector 2 π r = ( π l 2 / 2 π l )x 2 π r = π rl Surface area of cone l 2 π r l 2 π r l