∠ 1=∠2.AE=MC,∠MCN =∠5;
(2) solution: true. Intercept a1h = m1c1on a1;
(3) Multiply ∠ AMN = 60 = (3? 2)3× 180,∠a 1m 1n 1 = 90 =(4? 2)4× 180 ,
Guess: ∠ anmmnnn = (n? 2)n× 180。