Question

如图,长方形纸片ABCD,点E,F分别在边AB,CD上,连接EF,将角BEF对折,点B落在直线EF上

Answer 1

∠FEM=1/2∠BEF

∠FEN=1/2∠AEF

∠NEM=∠FEM+∠FEN

=1/2∠BEF+1/2∠AEF

=1/2(∠BEF+∠AEF)

=1/2*180°

=90°是它吗