Multiple choice

The radius and length of an arc of a circle are 35 cm and 22 cm respectively The angle subtended by the arc at the centre of the circle is

  1. $\displaystyle 72^{\circ} $
  2. $\displaystyle 45^{\circ} $
  3. $\displaystyle 36^{\circ} $
  4. $\displaystyle 40^{\circ} $
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Arc length L = r * theta (in radians). 22 = 35 * theta. theta = 22/35 radians. To convert to degrees: (22/35) * (180/pi) = (22/35) * (180 / (22/7)) = (22/35) * (180 * 7 / 22) = 180 / 5 = 36 degrees.

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