c² = a² + b² - 2 a b cos C
2 a b cos C = a² + b² - c²
cos C = (a² + b² - c²) / 2ab
C = arccos( (a² + b² - c²) / 2ab )
C = arccos( (17² + 8² - 16²) / (2 (17)(8) ) )
C ≈ 69.11°
Answer: 69.1
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