The diameter if base of a right circular cone is 7 cm and height is 10 cm , then what is its lateral surface area?

Given that,
Diameter of a right circular cone = 7 cm
∴ Radius of a right circular cone = 7/2 cm
and slant height of a right circular cone (l) = 10 cm
∴ Lateral surface area of a cone = πrl = (22/7) x (7/2) x 10
= 11 x 10 = 110 cm²