2. 10.4 Inscribed Angles February 16, 2012
10.4 Inscribed Angles & Polygons
Inscribed angle: vertex is on circle & sides contain chords
Intercepted arc: lies inside of inscribed angle & endpoints on angle
Measure of Inscribed Angle Theorem: measure of inscribed angle
A
= 1/2 of intercepted arc
D C
m<ADB = 1/2 mAB
B
HW pg. 676 #418 evens 2
4. 10.4 Inscribed Angles February 16, 2012
Theorem 10.8: If 2 inscribed <s intercept the same arc,
then the <s are ≅.
A
D <ADB ≅ <ACB
B
C
HW pg. 676 #418 evens 4
5. 10.4 Inscribed Angles February 16, 2012
Inscribed Polygon: all vertices line on a circle
Circumscribed circle: contains inscribed polygon
circumscribed circles
inscribed triangle inscribed pentagon
http://www.youtube.com/watch?v=kSEZReRYPZ8
Theorem 10.9: If a right is inscribed, then hypotenuse is diameter.
HW pg. 676 #418 evens 5
6. 10.4 Inscribed Angles February 16, 2012
Inscribed Quadrilateral Theorem: a quad can be inscribed iff
its opposite <s are supplementary.
HW pg. 676 #418 evens 6
