Mathematics for IGCSE & O level - Mensuration (Section 12 - No. 46)
If you only know the curved surface area of a cone and the radius of its base, which formula can you use to find the slant height?
Slant height = curved surface area / πr
Slant height = curved surface area / πr²
Slant height = curved surface area * πr
Slant height = curved surface area - πr
Explication
Curved surface area of a cone is πrl, therefore slant height (l) = curved surface area / πr.