As shown in the figure, in the pentagonal ABCDE, ∠ BAE = 120 °, ∠ B = ∠ e = 90 °. AB = BC, AE = De, find a point m, N on BC, de respectively, so that the perimeter of △ amn is the smallest, then the degree of ∠ amn + ∠ anm is () why extend AB to a 'to make Ba' = AB, extend AE to a 'to make AE = EA' ', connect a'm, a'n, then the perimeter of △ amn is the smallest?

As shown in the figure, in the pentagonal ABCDE, ∠ BAE = 120 °, ∠ B = ∠ e = 90 °. AB = BC, AE = De, find a point m, N on BC, de respectively, so that the perimeter of △ amn is the smallest, then the degree of ∠ amn + ∠ anm is () why extend AB to a 'to make Ba' = AB, extend AE to a 'to make AE = EA' ', connect a'm, a'n, then the perimeter of △ amn is the smallest?

Process: ∠ amn + ∠ anm = 120 ° extend AB to a 'to make Ba' = AB, extend AE to a 'to make AE = EA' ', then the intersection of a'a' 'and BC, ED is the M and N, and ∠ amn + ∠ anm = 2 ∠ a' + 2 ∠ a '' = 2 (180 - ∠ BAE) = 120 ° I hope it is helpful for you