Please help me I keep getting the last row wrong.

Answer:
B = 48°
b = 29.7
c = 39.1
Step-by-step explanation:
You have made a Mistake which is C = 102° Not 120°
So, Lets begin with the Problem
Since the Sum of Interior Angles of the Triangle = 180 °
Then A+B+C=180
Then 30+B+102=180
Then B+132=180
Subtract 132 from Both sides
B = 180 - 132 = 48°
Applying Law of Sines
[tex]\frac{a}{sinA} =\frac{b}{sinB}=\frac{c}{sinC}[/tex]
by substituting
[tex]\frac{20}{sin30} =\frac{b}{sin48}=\frac{c}{sin102}[/tex]
Then [tex]b=\frac{20sin48}{sin30} =29.7[/tex]
Then [tex]c=\frac{20sin102}{sin30} =39.1[/tex]