Question

Find the value of C in a triangle where a = 6, b = 8, and c = 12.

Answer 1

Answer: 117°

Step-by-step explanation:

Use the Law of Cosines:

c² = a² + b² - 2ab · cos C

12² = 6² + 8² - 2(6)(8)(cos C)

144 = 36 + 64 - 96 cos C

144 = 100 - 96 cos C

44 = -96 cos C

$-\dfrac{44}{96}=cosC\\\\\\cos^{-1}\bigg(-\dfrac{44}{96}\bigg)=C$

117° = C