Question

The length of the arc is $12$ cm and its angle is $2\pi$. Find its radius. (Use $\pi =3$)

• A. $9$ cm
• B. $2$ cm
• C. $18$ cm
• D. $15$ cm

Answer 1

The correct option is B $2$ cm

We know that length of subtended arc $=$ $\theta r$
Here, $r=?$ cm
$s=12$ cm
$\theta =2\pi$
So, $12=2\times 3\times r$
$r=\frac{12}{2\times 3}$

$r=2$ cm