Question
Determine the angle (in radians) subtended at the centre of a circle of radius 3 cm by each of the following arcs:
arc of length 6 cm
arc of length 3π cm
arc of length 1.5 cm
arc of length 6π cm
Determine the angle (in radians) subtended at the centre of a circle of radius 3 cm by each of the following arcs:
arc of length 6 cm
arc of length 3π cm
arc of length 1.5 cm
arc of length 6π cm
The arc length can be expressed in terms of centered angle in degrees or radians
l =\dfrac{n\pi r}{180\degree } = r\theta
In this question, the angle is required in radians. So the arc length formula to be used is
l = r\theta =3\theta
(r =3 cm)
arc of length 6 cm
l = 6 cm
then
6 = 3\theta
\theta =2
arc of length 3π cm
l = 3π cm
3π = 3\theta
\theta =\pi
arc of length 1.5 cm
l = 1.5 cm
1.5 = 3\theta
\theta =0.5
arc of length 6π cm
l = 6π cm
6π =3\theta
\theta =2\pi