1. **State the problem:** Fill in the blanks for the angle relationships in the triangle. 2. **Recall angle relationships in triangles:** - Angles opposite equal sides are equal. - The sum of angles in a triangle is always 180°. 3. **Given:** - m∠1, m∠2, m∠4 are angles in the triangle. 4. **Find m∠1 and m∠2:** - From the figure and angle relationships, m∠1 equals the angle opposite it (often m∠3 or another angle depending on the figure). - Similarly, m∠2 equals its corresponding opposite angle. 5. **Sum of angles:** - Use the triangle sum theorem: $$m\angle1 + m\angle2 + m\angle4 = 180^\circ$$ 6. **Answer:** - m∠1 = m∠3 (or the angle opposite to ∠1) - m∠2 = m∠5 (or the angle opposite to ∠2) - m∠1 + m∠2 + m∠4 = 180° **Regarding the rest of the problems:** - Set 3 #2: The calculations for m∠1 = 100° and m∠2 = 65° are correct. - Set 4 #1: Solving 3x = 30 gives x = 10, but the user wrote x = 6, which is incorrect. - Set 4 #2: Solving 7x + 5 = 180 gives x = 25, which is correct. Hence, Set 3 #1 is explained above, Set 3 #2 and Set 4 #2 are correct, but Set 4 #1 has a mistake in the solution.