Question

solve the triangle a=1 b=2 C=50 degrees

Answer 1

guessing that you are describing a triangle ABC , use the cosine law

c^2 = a^2 + b^2 - 2(a)(b)cosC
= 1 + 4 - 2(1)(2)cos50
= 2.42885
c = 1.5585

Now use the sine law to find a second angle.
The use the angle sum of a triangle to find the third angle.