Question

Assume ๐›ผ is opposite side a, ๐›ฝ is opposite side b, and ๐›พ is opposite side c. Assume that a = 7sqrt(3), b = 7sqrt(2), ๐›ฝ = 45ยฐ. Determine whether there is no triangle, one triangle, or two triangles. Then solve each triangle, if possible. Enter your answers so that ๐›ผ1 is greater than ๐›ผ2.)
(To the extent possible use standard angles to simplify your responses. When necessary express your answers using the functions sin, cos, sinโˆ’1, cosโˆ’1. If there is no solution enter IMPOSSIBLE.)

Answers

oobleck
sin๐›ผ/7โˆš3 = sin45ยฐ/7โˆš2
now, ๐›พ = 180-๐›ผ-๐›ฝ
and you can use the law of sines/cosines to find c
mathhelper
You are looking at what is called the "ambiguous case"

Let's find angle ๐›ผ , using the sine law

sin๐›ผ/7โˆš3 = sin 45/7โˆš2
sin ๐›ผ = 7โˆš3(โˆš2/2) / 7โˆš2 = โˆš3/2
so ๐›ผ = 60ยฐ or ๐›ผ = 120ยฐ , since the sine is positive in both the 1st and 2nd quadrants.

So it looks like we could have 2 triangles.
Triangle #1, angles B = 45, angle A = 60 and angle C = 75ยฐ
find the missing side c using the sine law.

triangle #2, angles 45, 120 and 15ยฐ , again find the missing side.
Side c should be the same for both.

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