1. A tangent at any point of circle is Perpendicular to the radius through the point of contact.
AP = AQ
∠P + ∠O = 180°
PO is angle bisector of ∠P & ∠O
3. If two chords AB and CD are crossing each other at a center P then,
PA × PB = PC × PD
If AB || CD
then ∠EOF = 90°
∠1 = ∠2
∠ACB = 90°
AB + CD = AC + BD
Area of circle=
10. AB = CD = Direct Common tangent
AB = CD =
11. AB = CD Transverse Common Tangents
If CD = radius
then ∠CED = 60°
16. if CD is perpendicular bisector of the common chord AB ,then
The length of AB =
17. Common chord of two equal circle after intersection.
AB = =
(a) If any trapezium ABCD, where AB || CD, is inscribed is a circle, Then its non-parallel sides (i.e AC and BD), are equal and AD = BC.