Question

如图,A,B,C,D,E,F是△MNR的三条边上的点,AB//DE,BC//EF,CD//AF.

Answer 1

（1）∠1=∠M+∠MFA

∠4=∠RED+∠R

∠M=∠RED

∠MFA=∠R

∠1=∠4

（2）∠1+∠2+∠3

=∠M+∠MFA+∠N+∠NCB+∠N+∠NBC

=∠M+∠R+∠N+∠R+∠N+∠M

=360