Circle GeometryCircle Geometry

Conjecture: a mathematical statement that appears likely to be true, based on your observations, but has not been proven

Conjectures about ARCs & Conjectures about ARCs & ANGLES…ANGLES…3. The measure of a central angle

equals the measure of its corresponding minor arc

Conjectures about ARCs & Conjectures about ARCs & ANGLES…ANGLES…4. The measure of a central angle

is 360o minus the measure of the major arc with the same endpoints as the central angle

Conjectures about ARCs & Conjectures about ARCs & ANGLES…ANGLES…5. The measure of an inscribed

angle in a circle equals half of the measurement of the arc it intercepts (or the central angle)

inscribed angle

central angle

6. All inscribed angles that intercept the same arc will have the same measurement

Conjectures about ARCs & Conjectures about ARCs & ANGLES…ANGLES…

arc CB

7. If an inscribed angle intercepts a semicircle, then it has a measure of 90o

Conjectures about ARCs & Conjectures about ARCs & ANGLES…ANGLES…

Conjectures about Conjectures about CHORDS…CHORDS…1. The

perpendicular bisector of a chord will pass through the centre of the circle

Conjectures about Conjectures about CHORDS…CHORDS…2. Congruent

chords in a circle are equal distance from the center of the circle

Conjectures about Conjectures about TANGENTS…TANGENTS…8. When a

tangent line and a radius intersect at the point of tangency, the two lines will be perpendicular

radius

tangent line

point of tangency

Conjectures about Conjectures about TANGENTS…TANGENTS…9. If two tangent segments

intersect outside a circle, then the tangent segments have equal measures