Post on 16-Jan-2016
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8-3A Inscribed Angles
What is an inscribed angle?
What is the relationship between an inscribed angle and its
intercepted arc?
Find the measure of each arc
• mDE
• mAED
• mEBDA
B
C
D
E
54°
54°
180°
306°
What kind of angle is angle ECD?
Central angle
DefinitionHis name was inscribed on the award.
The square is inscribed in the circle.
A
B
CAn inscribed angle is an angle with its vertex on a circle and sides that contain chords of the circle.
Sizing Up Inscribed Angles
• Measure the central angle
• What is the measure of the arc AB?
• Measure the inscribed angle
• Compare the measure of the central angle and the inscribed angle.
A
BC
D
ACB
ADB
Inscribed Angle Theorem
The measure of an inscribed angle is half the measure of its intercepted arc.
A
B
C
Find the measure of each angle or arc indicated by a variable.
24°
x°
160°
y°
C
z°
48°
80°
90°
Theorem
If two inscribed angles intercept the same arc, then they are congruent.
A
B
C
D
Theorem
An inscribed angle that intercepts a semicircle is a right angle.
• What is an inscribed angle?
An inscribed angle is an angle with its vertex on a circle and sides that contain chords of the circle.
• What is the relationship between an inscribed angle and its intercepted arc?
The measure of an inscribed angle is half the measure of its intercepted arc.
Assignment 8-3A
Page 586, 1-6, 8-12, 29-36