1. Tardigrade
  2. Question
  3. Mathematics
  4. A piece of paper in the shape of a sector of a circle (see Fig. 1) is rolled up to form a right-circular cone (see Fig. 2). The value of the angle θ is

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. A piece of paper in the shape of a sector of a circle (see Fig. $1$) is rolled up to form a right-circular cone (see Fig. $2$). The value of the angle $\theta$ isMathematics Question Image

KVPYKVPY 2011

Solution:

We know, $\theta=\frac{A B}{O B}$
image
From first figure,
$A B =2 \pi r $
$O B =13 $
$\therefore 2 \pi(5) =13 \theta$
$ \Rightarrow \theta=\frac{10 \pi}{13} $