Solving the details of a junior high school math problem is urgent! ! !</p><p>1, as shown in the figure: because HD⊥BC and HF⊥AB, H, F, B and D are four * * * cycles.</p><p>Then ∠DFH=∠DBH, and the sam

Solving the details of a junior high school math problem is urgent! ! !

1, as shown in the figure: because HD⊥BC and HF⊥AB, H, F, B and D are four * * * cycles.

Then ∠DFH=∠DBH, and the sam

Solving the details of a junior high school math problem is urgent! ! !

1, as shown in the figure: because HD⊥BC and HF⊥AB, H, F, B and D are four * * * cycles.

Then ∠DFH=∠DBH, and the same four points of b, c, e and D * * * are rounded: ∠EFH=∠DBH.

So ∠DFH=∠EFH, so FH is the bisector of ∠DFE, which can also prove that:

HD is the bisector of ∠FDE, so H is the intersection of two bisectors of △DEF.

So h is the heart of △DEF.

2. extend AG to BC in d and AI to BC in e.

then what AG？ =? 2GD and AE are bisectors of angles.

∴? AC/CE？ =? AB/BE

Available? CE？ =? 2

Even CI and CI are angular bisectors.

∴? AI/IE？ =? AC/CE？ =? 4/2? =? 2 ? And AG/GD=2.

∴? IG？ //? emergency department

∴? IG？ /? Ed. =? AG？ /? AD？ =? 2/3

Ed. =? CD？ -? CE？ =? 1/2

∴? IG？ =? 1/3 ? ∴? GI？ /? BC? =? 1? /? 15 ? As shown in the figure