1. **State the problem:** We have a large triangle composed of smaller triangles with given angles 40°, 30°, and 50°, and we need to find the unknown angle marked with a question mark in the bottom-right corner. 2. **Recall the triangle angle sum rule:** The sum of the interior angles of any triangle is always $$180^\circ$$. 3. **Analyze the given angles:** The smaller triangles have angles 40°, 30°, and 50°. Since these are parts of the larger triangle, the unknown angle can be found by subtracting the sum of the known angles from $$180^\circ$$. 4. **Calculate the sum of known angles:** $$40^\circ + 30^\circ + 50^\circ = 120^\circ$$. 5. **Find the unknown angle:** $$180^\circ - 120^\circ = 60^\circ$$. 6. **Conclusion:** The unknown angle marked with the question mark is $$60^\circ$$.