Sectors, Arcs, Segments in Circles, using Degrees

This applet demonstrates lengths of arcs, areas and perimeters of sectors and areas of segments of circles.

Author and programmer: Ron Barrow

UK Years 10-11, KS4 GCSE, Shape and Measure
US Grades 7 - 10 Measurement


Instructions below      Waldomaths video    Waldomaths video    See also:   This applet using Radians   Print

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How to Use this Applet

On the circle you can move points A and B around by clicking them and dragging them with your mouse to new positions. This also can change the size of the circle.
Clicking the circular buttons at the bottom has these effects:
Clicking "sector" highlights a sector of the circle.
Clicking "arc" highlights an arc on the circle's circumference
Clicking "triangle" highlights the isosceles triangle formed by A, B and the centre O

Clicking "segment" highlights either the major segment or the minor segment formed by the chord AB.
Clicking "show working" displays some calculations at the right of the screen. You should study these carefully. Enjoy yourself while you learn these important techniques.