Answer:
Step-by-step 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
