Please help ASAP. I need someone to check my Geometry answer and explain why I am right or wrong. REAL ANSWERS ONLY. 20 PTS!

Answer:
you are right
Step-by-step explanation:
Use the law of law of cos
c^2=a^2+b^2﹣2abcos√angle
(2√13)^2=52=4+36-24cos(a)
cos(a) = -12/24 = -1/2
a = 120 degrees
so yes, you are right