SOLUTION: Given △ABC with C=48°、a=12 , and b=8. 1.Solve for c, rounding your answer first to the nearest tenth and then to the nearest hundrenth. 2.Use the Law of Sines with

Algebra ->  Trigonometry-basics -> SOLUTION: Given △ABC with C=48°、a=12 , and b=8. 1.Solve for c, rounding your answer first to the nearest tenth and then to the nearest hundrenth. 2.Use the Law of Sines with      Log On


   

Question 1064381: Given △ABC with C=48°、a=12 , and b=8.
1.Solve for c, rounding your answer first to the nearest tenth and then to the nearest hundrenth.
2.Use the Law of Sines with your first answer for c to find A.
3.Use the Law of Sines with your second answer for c to find A.
4.Use the Law of Cosines to find angle A using your first answer for c.
5.Use the Law of Cosines to find angle A using your second answer for c.
6.Find angle B using the two measures found in question 1.
7.Is angle A acute or obtuse? Why?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
From the law of cosines,
c%5E2=a%5E2%2Bb%5E2-2abcos%28C%29
c%5E2=12%5E2%2B8%5E2-2%288%29%2812%29cos%2848%29
c%5E2=144%2B64-192%28.6691%29
c%5E2=79.53
c=8.92
From the law of sines,
sin%28C%29%2Fc=sin%28B%29%2Fb
sin%2848%29%2F8.92=sin%28B%29%2F8
sin%28B%29=%288%2F8.92%29sin%2848%29
sin%28B%29=0.6667
B=41.81
So then,
A%2BB%2BC=180
A%2B41.81%2B48=180
A=90.2
Since A%3E90, obtuse.