Explicație:
CE//AB
AC secanta
=>mECD=mmABC=60(corespondente)
AP_|_BC =>AP_|_CD (D€BC)
ABC echi => AP=ABV3/2=>AP=12V3/2
=>AP=6V3cm
A ACD=AP*CD/2=6V3*6/2=18V3 cm²
AP_|_BC => P mij BC =>PC=AB/2=6cm=>
PD=12cm
In triunghiul APD,mAPD=90 =>T.P
AD²=AP²+PD²=>
AD²=108+144=>AD²=252=>AD=6V7cm
mECD=60 => mACE=60 (180-mACB-mECD)
=> CE bisect ACD => T.B AC/CD=AE/EC =>
12/6=AE/EC => 2/1=AE/EC => AE=2k si
EC=k => AD=3k => k=2V7 => AE=4V7 cm
