Theorem 86 (inscribed angle)
an inscribed angle is half the measure of the intercepted arc
Theorem 87 (chord-chord angle)
measure of a chord-chord angle is half the measure of the sum of arcs intercepted
Theorem 88 (secant-secant angle)
secant-secant angle is half the difference of the intercepted arcs
central angle
equals the intercepted arc
tangent-chord angle
half of the intercepted arc
tangent-tangent angle
half the difference of the major and minor arcs
What is an inscribed angle?
an angle whose vertex is on a circle and whose sides are determined by two chords
What is a tangent-chord angle?
an angle whose vertex is on a circle and whose sides are determined by a tangent and a chord that intersect at the tangent's point of contact
What is a chord-chord angle?
an angle formed by two chords that intersect inside a circle but do not at the center
What is a secant-secant angle?
an angle whose vertex is outside a circle and whose sides are determined by two secants
What is a secant-tangent angle?
an angle whose vertex is outside a circle and whose sides are determined by two tangents