Question

The wire of the length 121 cm is bent as to lie along the arc a circle of radius 180 cm. Find the degree, the angle subtended at the centre of arc.

Answer 1

Here's the answer 

Arc-length can be given by the formula : Ф / 360° × 2πr

Hence it is given that 121 cm is the arclength.

=> 121 = Ф / 360° × 2πr

= 121 =Ф / 360° × 2 * 22 / 7 * 180

= 121 = Ф / 360° × 360 * 22 / 7

= 121 = Ф * 22 / 7

=> Ф = 121 * 7 / 22

= 38.5°

Hence the angle subtended at the middle is 38.5