SOLUTION: Given Triangle ABC where a=12, b=10 and c=8 find the angles in degrees and minutes.

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Question 86015: Given Triangle ABC where a=12, b=10 and c=8 find the angles in degrees and minutes.
Answer by psbhowmick(878) About Me  (Show Source):
You can put this solution on YOUR website!
a=12, b=10 and c=8
Use the cosine rule
cos%28A%29+=+%28b%5E2+%2B+c%5E2+-+a%5E2%29%2F%282bc%29
cos%28A%29+=+%2810%5E2+%2B+8%5E2+-+12%5E2%29%2F%282x10x8%29
cos%28A%29+=+20%2F160
cos%28A%29+=+1%2F8
A+=+arccos%281%2F8%29+=+82.82%5Eo

Similarly,
cos%28B%29+=+%28c%5E2+%2B+a%5E2+-+b%5E2%29%2F%282ca%29
cos%28B%29+=+%288%5E2+%2B+12%5E2+-+10%5E2%29%2F%282x8x12%29
cos%28B%29+=+9%2F16
B+=+arccos%289%2F16%29+=+55.77%5Eo

Now we have to find angle C
C+=+180%5Eo+-+A+-+B
C+=+180%5Eo+-+82.82%5Eo+-+55.77%5Eo+=+41.41%5Eo