Circle Theorems

Circle Theorems

1. Theorems involving subtended angles

   • Angles subtended on the same arc are equal.
   • Angle Subtended by a diameter is a right angle
   • Angles at centre is double the angle at the circumfrences

2. Cyclic Quadrilaterals

   • The sum of the opposite angles of a cyclic quadrilateral is 180 degress

3. Tangents and Chords

   • A tangent to a circle is perpendicular to the radius.
   • Tangents to a circle froman external point ot the points of contact are equal in length.
   • The line joining an external point to the centre of the circle bisects the angle between the tangents

4. Alternate Segment Theorem

   • The angle between a tangent and a chord is equal to the angle in the alternate segment.