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6.06



Solve the triangle.


A = 33°, a = 20, b = 13 (1 point)




Cannot be solved


B = 20.7°, C = 146.3°, c ≈ 23.7


B = 20.7°, C = 126.3°, c ≈ 17.8


B = 20.7°, C = 126.3°, c ≈ 29.6



2. State whether the given measurements determine zero, one, or two triangles.


C = 30°, a = 32, c = 16 (1 point)




Two


Zero


One



3. Two triangles can be formed with the given information. Use the Law of Sines to solve the triangles.


A = 59°, a = 13, b = 14 (1 point)




B = 22.6°, C = 98.4°, c = 15; B = 157.4°, C = 81.6°, c = 15


B = 67.4°, C = 53.6°, c = 13.8; B = 112.6°, C = 8.4°, c = 13.8


B = 22.6°, C = 98.4°, c = 11.3; B = 157.4°, C = 81.6°, c = 11.3


B = 67.4°, C = 53.6°, c = 12.2; B = 112.

User Aucuparia
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8.4k points

1 Answer

3 votes

1. Solve the triangle. A = 33°, a = 20, b = 13 (1 point)


(a)/(\sin A) = (b)/(\sin B)


\sin B = (b)/(a) \sin A= (13)/(20) \sin 33 \approx 0.3540


B = \arcsin .3540 = 20.73^\circ

The supplement of B (which has the same sine) is around 159° so with A exceeds 180 degrees so we ignore it.


C = 180^\circ - A - B = 180 - 33 - 20.73 = 126.27^\circ


c = (\sin C)/(\sin A ) a= (\sin 126.27)/(\sin 33) (20) \approx 29.6

Fourth choice: B = 20.7°, C = 126.3°, c ≈ 29.6

2. State whether the given measurements determine zero, one, or two triangles. C = 30°, a = 32, c = 16 (1 point)


\sin A = (a)/(c) \sin C= (32)/(16) \sin 30 = 2(\frac 1 2)=1

That's unique, A=90°

One triangle.

3. Two triangles can be formed with the given information. Use the Law of Sines to solve the triangles. A = 59°, a = 13, b = 14 (1 point)


\sin B = (b)/(a) \sin A= (14)/(13) \sin 59 \approx 0.9231

There are two triangle angles with this sine, supplementary to each other,


B_1 \approx 67.4 \textrm{ or } B_2 \approx 180- 67.4 = 112.6

Since when combined with A=59° neither A+B exceeds 180°, we have two valid triangles.


C_1 = 180 - 59 - 67.4 = 53.6


c_1 = (\sin C_1)/(\sin A ) a = (\sin 53.6)/(\sin 59) (13) = 12.2


C_2 = 180 - 59 - 112.6 = 8.4


c_2 = (\sin C_2)/(\sin A ) a = (\sin 8.4)/(\sin 59) (13) = 2.2

That's the last choice, suitably edited:

B = 67.4°, C = 53.6°, c = 12.2; B = 112.6°, C = 8.4°, c = 2.2

User Snakecharmerb
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8.4k points