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Sau coroana!!Va rog!!!

Sau CoroanaVa Rog class=

Răspuns :

inΔPAB avem:DC║AB⇒ΔPAB~ΔPDC⇒PD/PA=PC/PB=DC/AB
dar PA=PD+AD;PB=PB=PC+BC⇒PD/(PD+AD)=PC/(PC+BC)=21/36
PD/(PD+20)=21/36⇒36PD=21(PD+20)⇒PD=28cm⇒PA=PD+AD=28+20⇒
⇒PA=48cm
PC/(PC+BC)=21/36⇒PC/(PC+25)=21/36⇒36PC=21(PC+25)⇒PC=35 cm⇒
⇒PB=PC+BC=35+25⇒PB=60cm