Question

Find the volume and the curved surface area of a cylinder whose base is 28cm and its height is 21 cm.​

Answer 1

Answer:

Given, height of cone (h)=28cm. 

Radius of base (r)=21cm 

Slant height of the cone l=r2+h2

 Curved surface area =(21)2+(28)2=441+784=1225=35×35=35cm=πrl=722×21×35=2310cm2

Total surface area of the cone

=πr(l+r)=722×21(35+21)=22×3×56=3696cm2

Volume of the cone =31πr2h

=31×722×21×21×28

=