AOC=BOD
AOD=BOC
OD OE
①BAD= C CAD= B
②AD2=BD·CD
③AB2=BD·BC
④AC2=CD·BC
P=A+B+C
A+B=C+D
B=D
P=90+A/2
P=A/2
P=90-A/2
AP平分BAC
PB=PC
C C C F
E
A
B
C
O E
F
G F
O
D
B C