Question

The total surface area of frustum cone is $1200f{t}^2$. The radius of a top cone is $3$ and the bottom cone is $6$ ft. What is the curved surface area of a frustum of cone?

Answer 1

Total surface area $=\pi (R+r)s+\pi R^2+\pi r^2$
Curved surface area $=\pi (R+r)s$
Therefore, $1200=$ Curved surface area $+\pi (6^2+3^2)$
$1200=$ Curved surface area $+3.14\times (36+9)$
$1200-141.3=$ Curved surface area
Curved surface area $=1058.7$ ft.