Download There are twelve rules in circle geometry

Rules of Circle Geometry
The circle is the most fascinating shape in mathematics. The circle is a locus of all the
points that are the same distance from one point.
There are twelve rules in circle geometry
1.
Equal arc/chord subtend equal angles at the centre. Equal angles stand on
an equal arc/chord.
2.
Equal chords are equal distance from the centre. Chords that are equal
distance from the centre are equal.
3.
The line from the centre of a circle to the centre of a chord is perpendicular to
the chord. A perpendicular line from the chord to the centre bisects the chord.
4.
The angle at the centre is twice the angle standing on the same chord/arc.
5.
Angles on the same arc are equal.
6.
Angles on a semi-circle is 90°
7.
Cyclic Quadrilaterals are quadrilaterals where all four corners lie on a circle.
The opposite angles of cyclic quadrilaterals are supplementary.
8.
x+y=180°
The angle between the radius and a tangent is 90°
9.
Tangents drawn from an external point are equal.
10.
Two chords or secants (AB and CD) intersecting at X, then AX.BX = CX.DX
11.
A secant and a tangent (ABX and CX) intersecting at X, then AX.BX=CX^2
12.
The angle between a chord and a tangent is equal to the angle in the
alternate segment.