Monday 9 January 2012

SOME IMPORTANT POINTS TO REMEMBER (Areas related to circles)

  • If two circles touch internally, then the distance between their centres is equal to the difference of their radii.
  • If two circles touch externally, then the distance between their centres is equal to the sum of their radii.
  • Distance moved by a rotationg wheel in one revolution is equal to the circumference of the wheel.
  • The number of revolutions completed by a rotating wheel in one minute = Distance moved in one minute/ Circumference.
  • A minor sector has an angle , subtended at the centre of the circle, whereas a major sector has no angle.
  • The sum of the arcs of the major and minor sectors of a circle is equal to the circumference of the circle.
  • The sum of the areas of major and minor sectors of a circle is equal to the area of the circle.
  • The boundary of a sector consists of an arc of the circle and the two radii.
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2 comments:

  1. Mansi10 January 2012 at 07:54

    I want to know the solutions of following questions:-
    1-Area of a sector of a circle is 1/6 to the area of circle. Find the degree measure of its minor arc.
    2-If the diameter of a semi circle protractor is 14 cm. Find its perimeter.

    ReplyDelete
  2. Quadd Advertisements11 January 2012 at 03:59

    @mansi
    Please check your solutions at following link:

    http://quaddomaths.blogspot.com/2012/01/you-ask-we-reply.html

    ReplyDelete

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