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PRESENTATION
CIRCLE GEOMETRY
B
C
D
E
A
All angles made by
diameter on the
circumference of circle
are 90 degree.
 Angle ABD = 90
 Angle ACB = 90
 Angle AEC = 90
A B
CD
All angles made by a chord on
the circle are equal.
 Angle ACB = Angle BDA
T
P
R Q
B
O
C
A
Φ
Φ
2Φ
Φ
 Angle TPR = Angle PQR  Angle BOQ =2×angle BAC
B
C
A
A
 Exterior Angle A = angle C
 A+C = 180
 B+D = 180
Φ
Φ
B
P
PA = PB
CIRCLE GEOMETRY
D
P
Q
T
PA = PB
O
Angle PTQ = 2 × Angle OPQ
P
Q
T
PA = PB
+ = 180 degree
+ = 360 degree
= 2
CIRCLE GEOMETRY
o
BP
90
If in a circle a perpendicular is
drawn from center to a chord
then it divides it in two equal
halves.
OD perpendicular to AB at D
Then AD=DB
D
B
Q
P
PQ×PQ = PB×PA
A
Tangent drawn on the
circumference of a circle is
perpendicular to the line drawn
for the center of that circle
90
CIRCLE GEOMETRY
M
If AC=BC=AB and r is the radius of
both the circles
Then, CD= 2 r & AM=MB= r
O BA
P
Circle with single common tangent
By property of tangent in figure
OP=OA &OP=OB
Therefore AO=OB
CIRCLE GEOMETRY
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Math circle geometry

  • 1.
  • 2.
    CIRCLE GEOMETRY B C D E A All anglesmade by diameter on the circumference of circle are 90 degree.  Angle ABD = 90  Angle ACB = 90  Angle AEC = 90 A B CD All angles made by a chord on the circle are equal.  Angle ACB = Angle BDA T P R Q B O C A Φ Φ 2Φ Φ  Angle TPR = Angle PQR  Angle BOQ =2×angle BAC
  • 3.
    B C A A  Exterior AngleA = angle C  A+C = 180  B+D = 180 Φ Φ B P PA = PB CIRCLE GEOMETRY D
  • 4.
    P Q T PA = PB O AnglePTQ = 2 × Angle OPQ P Q T PA = PB + = 180 degree + = 360 degree = 2 CIRCLE GEOMETRY
  • 5.
    o BP 90 If in acircle a perpendicular is drawn from center to a chord then it divides it in two equal halves. OD perpendicular to AB at D Then AD=DB D B Q P PQ×PQ = PB×PA A Tangent drawn on the circumference of a circle is perpendicular to the line drawn for the center of that circle 90 CIRCLE GEOMETRY
  • 6.
    M If AC=BC=AB andr is the radius of both the circles Then, CD= 2 r & AM=MB= r O BA P Circle with single common tangent By property of tangent in figure OP=OA &OP=OB Therefore AO=OB CIRCLE GEOMETRY
  • 7.
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