Question

Find the angle in degree subtended at the centre of a circle by an arc whose length is 15 cm, if the radius of the circle is 25 cm.

Answer 1

Here, r = 25 cm and S = 15 cm
Since S = r.θ,
15 = 25 x θ

∴ θ = `(15/25)^"c"`

∴ θ = `(3/5)^"c"`

= `(3/5 xx 180/pi)^circ`

= `(108/pi)^circ`

= `(108/3.14)^circ`    ...[∵ π = 3.14]

= (34.40)° ...(approx.)

∴ The required angle in degree is `(108/pi)^circ` or

(34.40)° ...(approx.).