Answer:
35°
Step-by-step explanation:
From the sketch made, to obtain B we use the cosine angle formula :
We have 2 so des and an included angle
Cos B = (a² + c² - b²) / 2ac
First we obtain the side c
c² = a² + b² - 2ab CosC
c² = 11.2² + 6.7² - 2(11.7 * 6.7) * cos 72
c = 11.13
Using the value of c
Cos B = (a² + c² - b²) / 2ac
CosB = (11.2² + 11.13² - 6.7²) / (2*11.2*11.13)
Cos B = 204.4269 / 249.312
B = Cos^-1(204.4269 / 249.312)
B = 34.9°
