海南省2015年中考题第23题如下:如图1-1,菱形ABCD中,点P是CD的中点,∠BCD=60°,射线AP交BC的延长线于点E,射线BP交DE于点K,点O是线段BK的中点.(1)求证:△ADP≌△ECP;(2)若BP=n·PK,试求出n的值;(3)作BM⊥AE于点M,作KN⊥AE于点N,连结MO、NO,如图1-2所示.请证明△MON是等腰三角形,并直接写出∠MON的度数. As shown in Figure 1-1, in the diamond ABCD, the point P is the midpoint of the CD, ∠ BCD = 60 °, and the extension of the ray AP to BC is at point E, and the ray BP is given DE At point K, point O is the midpoint of line segment BK. (1) Verify that: ΔADP≌ΔECP; (2) If BP = n · PK, try to find the value of n; (3) M, for KN ⊥ AE at point N, link MO, NO, as shown in Figure 1-2. Please prove △ MON is isosceles triangle, and directly write the degree of ∠ MON.