Post on 05-Jan-2016
description
10.6 More Angle Arc Theorems
After studying this section, you will be able to recognize congruent inscribed and tangent-chord angles; determine the measure of an angle inscribed in a semicircle and apply the
relationship between the measures of a tangent-tangent angles and its minor arc..
Theorem If two inscribed or tangent chord angles intercept the same arc, then they are congruent.
A
B
O
D
C
O
E
Theorem If two inscribed or tangent-chord angles intercept congruent arcs, then they are congruent.
Theorem An angle inscribed in a semicircle is a right angle.
A
C
B
Theorem The sum of the measures of a tangent-tangent angle and its minor arc is 180.
E
F
D
O
130
Minor arc DE = 130 find the measure of angle F.
Example 1N
L
O
S
V
Given circle O
Conclusions
Triangle LVE is similar to triangle NSE
E
Example 2
In circle O, segment BC is a diameter and the radius of the circle is 20.5 mm. Chord AC has a length of 40 mm. Find AB.
A
BO
C
Example 3
Given: circle O with tangent at B
A B
D
O
CAB�������������� �
AB CD���������������������������������������� ���
Prove: C BDC
Summary
Summarize what you have learned in this lesson.
Homework: worksheet