Greetings from Brasil...
We need to use the Cosine Law in Any Triangle, so we can use Heron's formula.
AC² = AB² + BC² - 2.AB.BC.COS B
AC² = 11² + 9² - 2.11.9.COS 63
AC ≈ 10,63
Heron's Formula:
Area = √[P.(P - AB).(P - BC).(P - AC)]
where P = (AB + BC + AC)/2
P = (11 + 9 + 10,63)/2 ⇒ P ≈ 15,31
Area = √[15,31.(15,31 - 11).(15,31 - 9).(15,31 - 10,63)]
Area ≈ 44,21 u.a.
