Question

The slant height of a closed cone is seven times the radius of its base.If the radius of the base is 3

cm.Find the total surface area in terms of
π​

Answer 1

Answer:

TSA of cone=

Step-by-step explanation:

r=3cm

h=7r

 =7*3=21cm

l=$\sqrt{h^{2}+r^{2} }$

=$\sqrt{21^{2} +3^{2} }$

=$\sqrt{441+9}$=$\sqrt{450}$

=21.21cm (appx)

TSA of cone=$\pi r(l+r)$

                   =$\pi *3(21.21 +3)$

                   =$\pi *72.63$cm

                   =$72.63\pi cm^{2}$