Work out cone surface area instantly with clear inputs, formula shown and shareable results.
The curved surface of a cone unrolls into a circular sector of radius l, giving lateral area πrl. Adding the circular base gives πr² + πrl = πr(r + l).
Lateral area
A = πrl, l = √(r² + h²)
Total area
S = πr(r + l)
Slant height is 5, so lateral area is 20π and total area 36π ≈ 113.097336 square units.
The lateral area uses the slant height l; only the volume uses the perpendicular height h.