The Law of Cosines: cos(C)=2aba2+b2−c2
cos(C)=2⋅AC⋅BCAC2+BC2−AB2=2⋅23⋅21232+212−162=966714≈0.74
∠C=arccos0.74≈42.3∘
cos(A)=2⋅AC⋅ABAC2+AB2−BC2=2⋅23⋅16232+162−212=736344≈0.47
∠A=arccos0.47≈62.1∘
∠B=180∘−(42.3∘+62.1∘)=75.6∘
Answer: ∠A=62.1∘,∠B=75.6∘,∠C=42.3∘.
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