Tangent Conjecture
a tangent to a circle is perpendicular the radius is drawn to the point of tangency
Tangent Segment Conjecture
Tangent segments to a circle from a point outside the circle are congruent
Chords Arc Conjecture
If 2 chords in a circle are congruent then their intercepted arcs are congruent
Chord Central Angles Conjecture
If 2 chords in a circle are congruent, then they determine 2 central angles that are congruent
Perpendicular to a Chord Conjecture
the perpendicular from the center of a circle to a chord is the bisector of the chord
Perpendicular Bisector of a Chord Conjecture
The perpendicular bisector of a chord passes through the center of a circle
Chord distance to center conjecture
2 congruent chords in a circle are equidistant from the center of the circle
Inscribed Angle Conjecture
the measure of an angle inscribed in a circle is 1/2 the measure of the intercepted arc
Inscribed Angles Intercepting Arcs Conjecture
Inscribed angles that intercept the same arc are congruent
Angles Inscribed in a Semicircle Conjecture
Angles inscribed in a semicircle are right angles
Cyclic Quadrilateral Conjecture
The opposite angles of a cyclic quadrilateral are supplementary
Parallel Lines Intercepted Arcs Conjecture
Parallel lines intercept congruent arcs on a circle
Circumference Conjecture
If C is the circumference and D is the diameter of a circle, then there is a number π such that C=dπ. If d=2r where R is the radius, then C=2πr
Arc Length Conjecture
The length of an arc equals the measure of the arc divided by 360 times the circumference