A rectangular paper of 44 cm long and 6 cm wide is rolled to form a cylinder of height equal to width of the paper. The radius of the base of the cylinder so rolled is :

Answer: Option C

Length of rectangle paper = Circumference of the base of cylinder
If r is the radius of the cylinder :
$$\begin{array}{rl}& \Rightarrow 44=2\pi r\\ & \Rightarrow r=\frac{44\times 7}{2\times 22}\\ & \Rightarrow r=7cm\end{array}$$