Hey, yet another question for you!

2. Triange ABC has AB=10cm, BC=7cm and angle B=80degree's Calculate

a) the area of the triangle

b) the length of CA

c) the size of the angle C

For a) i got 34.47cm^3

For b) i got 3.34cm

I can't figure out c)

If anyone can check my answers and help me with c) i'd be most grateful! :D