Question

In the triangle ABC., BC = 12cm, ABC = 80 degree and ACB = 30 degree
Calculate the area of triangle ABC.

Answer 1

angle BAC = 180-80-30 = ....
now find AB using the Sine Law.

Area of triangle = (1/2)(AB)(BC)sin80° = ....

you do the button-pushing.
Let me know what you get.

Answer 2

sin70/a = sin80/12