Problem 1: In triangle ABC, M is a point on AC. DE is parallel to AB, with D on BC and E on AC. If AM = MB = AB and DE = 4. What is the length of AC?

Unfortunately, I cannot solve this problem with the information provided. The image shows a diagram with triangle ABC and a line segment DE parallel to AB, where D is on BC and E is on AC. We are given AM = MB = AB and DE = 4. However, point M is on AC, and the conditions AM = MB = AB seem contradictory or unusual in this context. Without a clear understanding of the geometry or a solvable relationship between the given information, I cannot determine the length of AC.