Finding the Third Angle in a Triangle

In a triangle, two angles are known to be $50^{ ext{o}}$ and $70^{ ext{o}}$. A line parallel to one side of the triangle is drawn, thus creating a different set of angles with the other two sides of the triangle. What is the measure of the third angle in the triangle?

Remember that the sum of the angles in a triangle equals $180^{ ext{o}}$.