Find the degree measure of the angle subtended at the centre of a circle of diameter 60 cm by an arc of length 16.5 cm.

Angle in radians =

θ= where θ is central angle, l=length of arc, r=radius

Now,

= and r = 0.5 x diameter

= radians

θ in degrees =

θ in minutes = 0.5 x 60 = 30’

Therefore angle subtended at the center is 31° 30’