Tangents to CirclesCircles
Secants and Tangents Secant
2 points of intersection
Tangent 1 point of intersection
Point of Tangency
Radii _|_ Chord What would you conclude about the
following diagram?
P
A
B
X
R
Radii _|_ Chord What would you conclude about the
following diagram?
P
A
B
X
R
AX XB ?
Prove it!
Radii & Tangent What would you conclude about the
following diagram?
P
A
Radii & Tangent Does this help??
P
A
Radii & Tangent The tangent is perpendicular to the
radius at the point of tangency
P
A
Inscribed Angles & Arcs An inscribed angle has its vertex ON
the circle.
Inscribed Angles & Arcs An inscribed angle has its vertex ON
the circle.In
terce
pte
d
arc
Inscribed Angles & Arcs What type of inscribed angle forms a
minor arc?M
inor
arc
Inscribed Angles & Arcs What type of inscribed angle forms a
major arc?M
ajo
r arc
Inscribed Angles & Arcs What type of inscribed angle forms a
semicircle?S
em
icircle
Inscribed Angle Theorem An angle inscribed in an arc has a
measure equal to ½ the measure of the intercepted arc.
60 120
Inscribed Angle Theorem What is the missing measure?
20
?
Inscribed Angle Theorem What is the missing measure?
90
?
Inscribed Angle Theorem What is the missing measure?
?
Inscribed Angle Theorem What is the missing measure?
40
?
Theorem If two inscribed angles intercept the
same arc, then they have the same measure
40
4080
