I have to solve a triangle

the given information in triangle ABC is c=28.6,b=19.9 and A=48.1^o

i used the cosine law to get a which i found to be 21.3 is this correct?

i then tried to use the cosine law again to find one of the other angles

my work:

is this right? i don't think it is because we are working with obtuse triangles