1. **Problem:** Find the value of $x$ in a triangle with interior angles $55^\circ$, $25^\circ$, and $x^\circ$. 2. **Formula:** The sum of interior angles in any triangle is always $180^\circ$. $$55^\circ + 25^\circ + x^\circ = 180^\circ$$ 3. **Step:** Add the known angles: $$55^\circ + 25^\circ = 80^\circ$$ 4. **Step:** Substitute and solve for $x$: $$80^\circ + x^\circ = 180^\circ$$ $$x^\circ = 180^\circ - 80^\circ$$ $$x^\circ = 100^\circ$$ **Answer:** $x = 100^\circ$