Algebra 2
Chapter 13.5-13.6 REVIEW
When can you use…
A.
the Law of Sines
Name
Period
B.
the Law of Cosines
Solve for the missing angle, x. BE CAREFUL!!!
1.
2.
SSA
13
6
SSS
80
x
x
C.
Date
the new area formula
3. SSA
obtuse? Yes
75
43
38
48
41
x
17
17^2=6^2+13^2-2(6)(13)cosB
289= 205
84=-156cosB
84\-156
CosB = 122.6
Sin38\80 = SinA\43
SinA= 19.3
sin41\48 = SinC\75
Not A Triangle
Sin122.6\17 = sinA\6
SinA= 17.3
4. SSS
40
5.
18
x
22
40^2= 18^2+22^2-2(18)(22)cosC
1600 = 808
792= -792cosC
Not a Triangle
Obtuse? Yes
70
36
53
x
sin36\53 = sinC\70 = 50.9 or 129.1
6.
ASA
31
22
87
x
22+87=109 180-109=71
Solve for the missing side, x. BE CAREFUL!!!
7.
8.
75
9.
x
83
42
70
13
x
20
50
10
20
x
Sin75
10.
11. 6
70
12.
x
37
60
50
11
28
130
x
4
x
13. Two observers are in lighthouses 25 miles apart. The observer in the first lighthouse spots a ship in distress at an
angle of 15 with the line between the lighthouses. The other observer spots the ship at angle of 35 with the line
between the lighthouses. How far is the ship from each lighthouse?