Question

if a=15.3cm b=20.9cm c=34.7 then find alpha​

Answer 1

Answer:

where is the equation???

Answer 2

First, though, here's a diagram.



The formula for the Law of Cosine's is the following:

cosA=b2+c2−a22bc

cosA=82+122−522×8×12

cosA=0.953125

A=cos−1(0.953125)

A≈17.61˚or0.39 radians

Now for angle B:

cosB=a2+c2−b22ac

cosB=52+122−822×5×12

cosB=0.875

B=cos−1(0.875)

B≈28.96˚or0.51 radians

Finally for angle C:

cosC=a2+b2−c22ab

cosC=52