1. **Problem:** How do you calculate the angles in a triangle, and can I draw it too? 2. **Main formulas:** $$A+B+C=180^\circ$$ If you know two angles, the third angle is: $$\text{missing angle}=180^\circ-\text{known angle 1}-\text{known angle 2}$$ 3. **Important rule:** The three interior angles of every triangle always add up to $180^\circ$. 4. **Example calculation:** Suppose two angles are $50^\circ$ and $60^\circ$. Then the missing angle is $$180^\circ-50^\circ-60^\circ=70^\circ$$ 5. **Answer:** The third angle is $70^\circ$. 6. **Drawing:** I can draw a triangle to show the angles.