Question

the area of the base of of a right circular cone is 28.26 sq m if its height be 4m find its curved surface.

Answer 1

we know that area of base
$\pi \: r ^{2}$
so, 28.26 =
$\pi \: r ^{2}$
28.26= 22/7 ×r^2
$\sqrt{28.26 \times 7 \div 22}$
r= 2.99m
l
$\sqrt{r ^{2} + h ^{2} }$
l= 4.99m
curved surface area of cone =
$\pi \: r \: l$
22/7 ×2.99×4.99= 46.89m^2