What is a circle?• Circles are simple closed curves which divide the plane into two regions: an interior and an exterior.
Features OFCIRCLE……. … the distance from … the distance … the distance the the centre of across the circle,any Circle… around the circle to passing point Diameter through the centre of on the … its PERIMETER the circle circumference Radius
Minor MajorSegment Segment C AR … part of the touches a line which two joining d circumference of a at points on the the circumference or Ch circle circumference. one point only … chord divides circle From Italian tangere, to touch segments into two Tan g en t
Major sector SECANT Minor Sector
TANGENTA tangent to a circle is aline that intersects thecircle at only one point A B
A tangent isperpendicularto the radiusof a circle
THEOREMTHE LENGTH OF TWO TRIANGLES TO A CIRCLEFROM A EXTERNA POINT A EQUA A THEY N L RE L NDA EQUA INCLINED TO THE LINE SEGMENT RE LLYJOINING THE CENTRE A THA POINT T T
GIVEN: In c(o , r),tangents AP, PBAre shown from the external point P.To prove: AP=PB, APO= BPOConst.: join AO & BO Proof: In, ∆AOP=∆BOP OP=OP (common) OAP=OBP (Each 90°) AO=OB (radii of same circle) ∆AOP =~ ∆BOP (R.H.S) AP=PB, APO= BPO C.P.C.T HENCE PROVED…..