1. **State the problem:** We are given a triangle with interior angles 80°, 69°, and $x$° and need to find $x$. 2. **Formula and rule:** The sum of interior angles in any triangle is always 180°. 3. **Set up the equation:** $$80 + 69 + x = 180$$ 4. **Solve for $x$:** $$x = 180 - 80 - 69$$ 5. **Calculate:** $$x = 180 - 149 = 31$$ 6. **Answer:** The value of $x$ is 31°. --- Since the second problem involves classifying angle pairs and finding $x$ but lacks sufficient numeric or diagram details to solve $x$, we only solve the first problem as per instructions.