Question

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

• A. $50^{o}$
• B. $210^{o}$
• C. $100^{o}$
• D. $60^{o}$

Answer 1

Answer: (B)

$210^{o}$

Answer 2

Given the diameter of circular wire = 14 cm. Therefore length of wire = $14\pi cm$

Hence, required angle $= \frac{\text{Arc}}{\text{Radius}} = \frac{14\pi}{12} = \frac{7\pi}{6}$ radian

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