Download Lesson 10.4: Ellipses

10.4 Inscribed Angles

Inscribed angle: an angle inside the circle
with sides that are chords and a vertex on
the edge of the circle
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

Inscribed angle = ½ intercepted arc
An inscribed right angle, always intercepts a
semicircle
If two or more inscribed angles intercept the
same arc, they are congruent
A
Inscribed angles:
angle BAC, angle
CAD, angle DAE,
angle BAD, angle
BAE, angle CAE
X
B
Ex: Angle DAE = ½ arc DE
C
E
D
A
Inscribed angle BAC
intercepts a semicircle- so
angle BAC =90
B
C
D
F
E
G
Inscribed angles GDF and
GEF both intercept arc
GF, so the angles are
congruent
A. Find mX.
Refer to the figure. Find the measure of
angles 1, 2, 3 and 4.
ALGEBRA Find mR.
ALGEBRA Find mI.
ALGEBRA Find mB.
ALGEBRA Find mD.
The insignia shown is a quadrilateral inscribed in
a circle. Find mS and mT.