1. **State the problem:** Circle all triangles congruent to the first triangle in the row. 2. **Recall the congruence criteria:** Triangles are congruent if they have exactly the same size and shape, which means all corresponding sides and angles are equal. 3. **Identify the first triangle:** It is an inverted isosceles triangle with a horizontal top side. 4. **Check other triangles:** Look for triangles that are also inverted isosceles with the same orientation and size. 5. **Mark congruent triangles:** The triangles circled in pencil match the first triangle in size and orientation, so they are congruent. 6. **Complete the division problems:** - For 2) 1,764: Divide 1764 by 2. $$1764 \div 2 = 882$$ - For 9) 513: Divide 513 by 9. $$513 \div 9 = 57$$ - For 4) 296: Divide 296 by 4. $$296 \div 4 = 74$$ **Final answers:** - Congruent triangles are those circled in pencil matching the first triangle. - Division results: 882, 57, and 74 respectively.