Question

The circumference of a circle is $200$ feet and height is $12$ feet. Find its curved surface area of a cylinder.

• A. $2400{ft}^2$
• B. $2100{ft}^2$
• C. $2300{ft}^2$
• D. $2010{ft}^2$

Answer 1

The correct option is A $2400{ft}^2$

Circumference of cylinder is $C=2\pi r$

It is given that the circumference is $200$ feet, therefore,

$C=2\pi r\Rightarrow 200=2\pi r\Rightarrow r=\frac{200}{2\pi }=\frac{100}{\pi }$

Now, curved surface area of cylinder is $A=2\pi rh$

Here, the radius is $\frac{100}{\pi }$ ft and height is $12$ ft.

Thus,

$A=2\pi rh=2\pi \times \frac{100}{\pi }\times 12=2\times 100\times 12=2400$ ft${}^2$

Hence, the curved surface area of the cylinder is $2400$ ft${}^2$.