Introduction to Circular Measure: Arc Length and Sector Area

Introduction to Circular Measure: Arc Length and Sector Area

Secondary 3

The diagram shows the arcs \(AD\) and \(BC\) of two circles with centre \(O\).

The length of arc \(AD\) is \(8\pi\) cm and the length of \(DC\) is \(12\) cm.

\(OAB\) and \(ODC\) are straight lines and \(\angle AOD = \frac{\pi}{4}\) radians.

  1. Show that the radius of the sector \(OAD\) is \(32\) cm.
  2. Leaving your answers in terms of \(\pi\), find the
    1. perimeter of the shaded region.
    2. area of the shaded region.

Video Solution:

Video Solution

Video solution locked

A free account saves your progress; this video needs a course plan.

Solution:

Solution locked

680+ questions here come with free worked solutions. A free account saves your questions and progress; this one needs a course plan.

Answer:(i) \(32\text{ cm}\) (ii)(a) \((24+19\pi)\text{ cm}\) (ii)(b) \(114\pi\text{ cm}^2\)

Need help? Join our E-Maths tuition for O-Level success.

Learn more