10'5 Tangents

1
10.5 Tangents
2
Tangent line intersecting circle in 1 and only 1
pt
3
Thm 10.9 A line is tan to circle iff its
perpendicular to radius _at_ pt of tangency.
Example
4
3
x
X____
4
Example
Q
L
R
4
O
3
2
5
S
N
4
M
4
Is PQ tan to circle R?
P
Is MN tan to circle L?
5
Thm 10.11 If 2 tangents are from the same ext
pt ? tangents are congruent.
6
Example
A
x _____
6x5
D
-2x37
Q
C
B
R
7
Example ?ADC is circumscribed about circle O.
Find perimeter of ?ADC if ECDEAF.
D
E
6
F
O
C
B
19
A
8
Types of Tangents
9
ASSIGNMENT

• 10.5 p. 556 (8-20 all, 23-26 all, 28, 34, 38-44
  even)