1. Essential question: How do I solve oblique triangles?
How do I deal with “SSA” when solving oblique triangles?
“the ambiguous case”

2. First, determine what case you have. (ASA, AAS, SSA, etc.)
Law of Sines
(“plug & chug”)
determine # of solutions
use the Law of Sines
to find them.

3. SSA Ex. 3 Solve ABC. A = 42°, a = 22 inches, & b = 12 inches a b
21.41°
b = 12 in A
c =
29.40 in
C =
116.59º
C = 180º - 42º º
= º
c = 29.40

4. Solving for 2 triangles:
Determine what you are given (SSS, SAS, SSA, etc)
Find all info as usual
Go back to the 1st angle you found… subtract it from 180 (180 - angle)
Add this new angle to the given angle
Compare that answer to 180
* if it is < 180 you have another triangle
* if it is > 180 you have only 1 triangle

5. SSA Ex. 5 A = 20.5°, a = 12, and b = 31 A = 20.5° a = 12 b a B1 =
64.78°
b = 31 A
C1 =
94.72º
c1 =
34.15
C = 180º º º
= 94.72º
c = 34.15

6. SSA Ex. 5 A = 20.5°, a = 12, and b = 31 Solution #2 b A = 20.5° a = 12
115.22°
b = 31 A
C2 =
44.28º
c2=
23.93
Remember
B2 = B1
Since A is less than 180 there are 2 triangles!
B2 = =
C = 180º º º
= 44.28º
c = 23.93

7. Ex. 4
a = 15, b = 25, and A = 85°
SSA
No solution!
Yea!
Error!!!