Answer:
The value of the length of the side C is 11.49.
Step-by-step explanation:
Cosine formula is applicable.
c² = a² + b² -2abcos(C)
substitute the values:
c² = (5)² + (12)² -2(5)(12)cos(72)
= 25 + 144 - 2 (60) (0.309)
= 169 - 37.08
c² = 131.92
square root both sides:
c = sqrt(131.92)
C = 11.49
