Dr. J's Maths.com
Where the techniques of Maths
are explained in simple terms.

Geometry - Circles - Mensuration.
Test Yourself 1.


Arc length 1.


  3. 4.
  5. 6.
Area of a sector 7. 8.


Area of a segment    
Mixed exercises 18.

The length of an arc of a circle is 2 π cm and the area of this sector is 8 π cm2 when an angle of θ is subtended at the center of the circle.


(i) the radius of the circle;

(ii) the angle (in degrees) subtended by the arc at the center of the circle.

Hint.Great question for learning technique.
Write out the two equations for Arc Length and for Area of the sector. We have simultaneous equations with the angle and the radius as unknowns.
DIVIDE the area equation by the arc length equation to isolate radius. Then substitute to find the angle.
REMEMBER THIS approach for a number of topics especially series!!!