Geometry & Trigonometry
Intermediate

Surface Area of a Cone

Total surface area of a cone with slant height l.

Formula

A=πr(r+l)A = \pi r(r + l)

Variables

rBase radius
lSlant height

Example

Radius 3, slant 5: A = π·3·(3+5) ≈ 75.4 square units.

Did You Know?

An ice-cream cone's paper wrap, unrolled, is a circular sector — the source of the πrl term.

conesurface area