The new curriculum standard synchronization unit exercises junior high school mathematics seventh grade B Volume 49 of Beijing Normal University Edition, the last second small question is shown in Figure 2: Find the angle A+ Angle B+ Angle C+ Angle D+ Angle E+ Angle F degrees. As can be seen from the figure, BE//CD, so ∠D=∠AGB (two straight lines are parallel and have the same angle).

Similarly ∠C=∠EIF.

So ∠ A+∠ B+∠ C+∠ D+∠ E+∠ F = ∠ A+∠ B+∠ EIF+∠ AGB+∠ E+∞.

Equal to the sum of the internal angles of two triangles, equal to 360.