The image you uploaded contains a geometry problem written in Vietnamese. It appears to be related to triangles and geometric properties involving perpendicular lines, congruent segments, and collinearity. Let's break down the key points from the text:

1. Given:

   • Triangle ABC, isosceles at A.
   • Segments BM and CN intersect at point H.
   • BM = CN and MN is parallel to BC.
   • AH is perpendicular to BC.

2. The problem asks to prove:

   • K is the midpoint of BC.
   • The lines AH, K, M are collinear.
   • The triangle is also compared with triangle AK.

I can assist with solving this geometric proof. Would you like me to go step by step through this problem? Let me know if you want me to explain any specific part of the question or if you'd like further details.

Here are some questions related to this problem:

1. What does it mean for two segments to be congruent in geometry?
2. How does parallelism between lines MN and BC help prove the required result?
3. What properties of perpendicularity could be useful in this proof?
4. Can you explain the concept of collinearity and why it matters in this context?
5. How would you approach proving that K is the midpoint of BC?

Tip: When working on geometric proofs, visualize the problem with diagrams to better understand the relationships between different points and lines.