∴∠BFE=∠BEF=36，

And ∠α=∠BFE+∠BEF,

∴∠α=72 ;

(2)∵NM⊥GB,AH⊥GB，

∴∠GNM=∠GHA=90，

And ∠G male * * *,

∴Rt△GMN ∽ Rt△GAH，

∴MN:AH=GM:GA，

While GA=5m, GM= 1m, MN=0.6m,

∴0.6:AH= 1:5，

∴ah=3m；

(3) In Rt△ABH, ∠ α = 72, AH=3,

∴tanα= AH BH, that is, tan 72 = 3bh,

∴BH= 3 3.0 = 1，

∴PH=PB+BH=3+ 1=4，

∫DC∨AP，

∴∠DCP=∠APH，

∴Rt△DCP ∽ Rt△APH，

∴ DP: ah = PC: ph, that is, DP: 3 = 9: 4.

∴pd= 27 ^ 4 = 6.75，

The height of this big tree is 6.75 meters.