Triangle Classification: Identifying an Obtuse Angle in Given Diagram

To determine if the triangle shown in the diagram is obtuse, we proceed as follows:

• Step 1: Identify that the diagram is indeed a triangle by observing the confluence of three edges forming a closed shape.
• Step 2: Appreciate the geometric arrangement of the triangle, focusing on the sides' lengths and angles visually.
• Step 3: Noticeably, the longest side of the triangle represents a noticeable tilt indicating the presence of an obtuse angle.

Based on the observation above, notably from the triangle's longest side against the base, it's clear that one angle is larger than $90^\circ$. Hence, the triangle in the diagram is indeed an obtuse triangle.

Therefore, the correct answer is Yes.