Identify the angles in the image and provide their values if available, or indicate if they are unknown.

Analysis of Angles:

The image displays several angles related to geometric figures.

• In the top portion of the image, angles with values 42° and 138° are indicated. Another angle is marked as 42°.
• In the triangle labeled with vertex A, an angle at vertex A is given as 31.5°. The angle at vertex B is marked with a question mark (?) and an arc, indicating it is an unknown angle. The angles at M are right angles (implied by the altitude from A to BC).
• The triangles ABC and the adjacent triangle are isosceles, as indicated by the tick marks on the sides.

Answer: The identified angles are 42°, 138°, 31.5°, and an unknown angle at B.