Question

A circular wire of radius 3 cm is cut and bent so as to lie along the circumference at a loop whose radius is 48 cm. The angle in grades which is subtended at the centre of the loop is

• A. 50 grades
• B. 20 grades
• C. 25 grades
• D. none of these.

Answer 1

Answer: (C)

Circumference of a circle of radius = 3 cm
= 2$\pi$ (3) = 6$\pi$ cm.
$\therefore$ length of the wire $(l)$ = 6 $\pi$ cm
Radius $(r)$ = 48 cm
Since $\theta =\frac{l}{r}=\frac{6\pi }{48}=\frac{\pi }{8}$ Radians = $\frac{200}{8}$ grades