Properties of Circles

Content

  • Symmetry Properties of Circles
  • Angle Properties of Circles
  • Tangents from an External Point
  • Angles in Cyclic Quadrilaterals

Symmetry Properties of Circles

Angle Properties of Circle

Tangents from an External Point

For a circle, two tangents, PX and PY can be drawn from an external point P.

Tangent makes an angle of 90° with radius of the circle.

PX = PY

< XOP = < YOP and < XPO = < YPO

Angles in Cyclic Quadrilaterals

A four sided polygon whose vertices touch the circumference of a circle is called Cyclic Quadrilateral.

Sum of diagonally opposite angles of a cyclic quadrilateral is 180°.

<a + <b = 180°

<c + <d = 180°