atul mishra ji
Post on 10-Aug-2014
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PPT ON CIRCLES
MADE BY :- ATUL MISHRA
CLASS : X H
ROLL NO. : 07
• A circle is the collection of all points in the plane, which are equidistant from a fixed point in the plane.• A circle is a plane figure.• Euclid discovered the circle.•The fixed point is called the centre of the circle • The fixed distance is called the radius of the circle.• The longest chord of the circle is the diameter of the circle.
.O
E
A
B C
D
Given:-EC = CD
TO PROVE :-OB =OA
O IS THE CENTRE OF CIRCLE
CONSTRUCTION:-JOIN OC
“IF THE LENGTH OF TWO CHORDS ARE EQUAL THEN THE ARC IS ALSO EQUAL AND EQUAL ARCS MAKE AN EQUAL ANGLE AT THE CENTRE .”
O is the centre.AB and CD are two equal chords.
TO PROVE:-Angle AOB = Angle COD
PROOF:-In AOB and COD
AO = CO (Radius of circle)
AB = CD (Given) OB = OD (Radius of
circle)By SSS Congruence rule, AOB is congruent to COD By corresponding part of congruent triangle
Angle AOB = Angle COD
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