Question

Find the surface area of the cone

Answer 1

Explanation:

slant height l =√(20²+(9/2)²)=√(400+81/4)=√(1681/4)=41/2

slant surface area=πrl

base area=πr²

Total surface area=πr²+πrl=πr(r+l)=π×(9/2)(9/2+41/2)=π×(9/2)×50/2=225π/2

=225×3.14/2

=225×1.57

=353.25 mm²