ppt on circles
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TRANSCRIPT
A POWERPOIN PRESENTATION ON CIRCLE
What is a circle?• Circles are simple closed curves which divide
the plane into two regions: an interior and an exterior.
Features OF CIRCLE…….
… the distance around the Circle…
… its PERIMETERDiameter
… the distance across the circle, passing through the centre of the circle
Radius
… the distance from the centre of the circle to any point on the circumference
… a line joining two points on the circumference.
… chord divides circle into two segments
… part of the circumference of a circleCho
rd
Tangent
Major Segment
Minor Segment
ARC
… a line which touches the circumference at one point only
From Italian tangere, to touch
Minor Sector
Major sectorSECANT
TANGENT
A tangent to a circle is a line that intersects the circle at only one point
A
B
A tangent is perpendicular to the radius of a circle
THEOREM
THE LENGTH OF TWO TRIANGLES TO A CIRCLE FROM AN EXTERNAL POINT ARE EQUAL AND THEY ARE EQUALLY INCLINED TO THE LINE SEGMENT JOINING THE CENTRE AT THAT POINT
GIVEN: In c(o , r),tangents AP, PB Are shown from the external point P.
To prove: AP=PB, APO= BPO Const.: 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…..