FG parallel AD, ∠GFP=∠HDP, △ GFP △ HDP, HP=PG, GF=HD.

The quadrilateral ABCD is a diamond, CD=CB, ∠HDC=∠ABC=60, ∠ABC=∠BEF=60,

∠GBc=60，∠HDC=∠GBC，△HDCP?△GBC

CH=CG，∠DCH=∠BCG

∠DCH+∠HCB=∠BCG+∠HCB= 120

∠hcg= 120,ch=cg,ph=pg,pg⊥pc,pg/pc=√3