Download Geometry 11-4 Inscribed Angles

Geometry 11-4 Inscribed Angles
• Inscribed angle- an angle whose vertex is
on the circle.
• Intercepted arc- the arc in between the
sides of the angle
AC is the
intercepted
arc
Theorem 1
• The inscribed angle is half the measure of the
intercepted arc.
A
100°
C
50°
B
1
mABC  AC
2
Example
• Find each measure.
mPRU
PS
Example
• Find the value of a.
Example
• Determine the value of x.
(3x – 20)°
x°
Theorem 2
• If a quadrilateral is inscribed in a circle, then
its opposite angles are supplementary.
D
C
A  C  180
B  D  180
A
B
Example
• Find the value of b.