Given, height of cone (h)=28cm.
Radius of base (r)=21cm
Slant height of the cone l=√r2+h2
=√(21)2+(28)2=√441+784=√1225=√35×35=35cm Curved surface area =πrl=227×21×35=2310cm2
Total surface area of the cone
=πr(l+r)=227×21(35+21)=22×3×56=3696cm2
Volume of the cone =13πr2h
=13×227×21×21×28
=12936cm3