Question

A circular wire of radius $7cm$ is cut and bend again into an arc of a circle of radius $12cm$. The angle subtended by the arc at the centre is.

• A. 50°
• B. 210°
• C. 100°
• D. 60°

Answer 1

Answer: (B)

210°

Answer 2

Given that diameter of circular wire = 14cm

Therefore length of circular wire = 14π cm.

$\therefore$ Required angle $= \frac{\text{arc}}{\text{radius}} = \frac{14\pi}{12} = \frac{7\pi}{6}$

$= \frac{7}{6}\pi.\frac{180^{o}}{\pi} = 210^{o}$.