Cho a // b, tính góc E3, góc C3, góc C2, góc E4

To solve for the angles E3, C3, C2, and E4, we need to use the properties of triangles and parallel lines. Here's a brief approach based on the information provided:

1. **E3 (Angle E)**: Use the angles around point E and properties of parallel lines. If DE || BC, then ∠E = ∠MAB (corresponding angles).

2. **C3 (Angle C)**: Calculate using the triangle sum theorem. In triangle ABC, if you know two angles, use \( \angle A + \angle B + C = 180^\circ \).

3. **C2 (Angle C2)**: If you can find the measure of angle C, then for angle MNP (inside the triangle), apply triangle properties.

4. **E4 (Angle E4)**: Similar to finding angle E3; use the property that angles adjacent on a line sum to 180° in case of any supplementary angles.

To determine specific measurements, numerical or geographical specifics need to be applied accurately as per the shape in question. Please double-check with the properties mentioned and the diagram to finalize the angles.