Answer:
27.63
Step-by-step explanation:
a² = b²+c² - 2bcCos(A)
a² = 11² + 9² - 2 x 11 x 9 x cos(38)
a = BC = 6.78
sin(A)/a = Sin(B)/b
sin(A)/6.78 = Sin(38)/9
sin(A) = Sin(38) x 6.78 / 9
sin(A ) = 0.463
SIn-1(0.463) = 27.63
