Determine whether the statement is true or false. Justify your answer.
1. If a triangle contains an obtuse angle, then it must be oblique.
2. Two angles and one side of a triangle do not necessarily determine a unique triangle.
3. When you know the three angles of an oblique triangle, you can solve the triangle.
4. The ratio of any two sides of a triangle is equal to the ratio of the sines of the opposite angles of the two sides.