Circles Flashcards
Theorem 1
Equal chords of a circle subtend equal angles at the centre
Theorem 2
If the angles subtended by two chords at the centre are equal,then the chords are equal
Theorem 3
The perpendicular drawn from the centre of a circle to the chord bisects the chord
Theorem 4
The line drawn through the centre of a circle to bisect a chord is perpendicular to the chord
theorem 5
equal chords of a circle are equidistant from the centre (for congruent circles as well)
theorem 6
chords equidistant from the centre are equal in length
theorem 7
if two chords are equal, then their corresponding arcs are equal
theorem 8
the angle subtended by an arc at the centre is double the angle subtended by it at any other remaining part of the circle.
theorem 9
angles in the same segment are equal
theorem 10
angles in a semicircle is a right angle
theorem 11
the sum of either pair of opposite angles in a cyclic quadrilateral is 180 degrees.
theorem 12
if the sum of a pair of opposite angles of a quadrilateral is 180 degrees, then the quadrilateral is cyclic