AC=√(BC^2-AB^2)=√(625-225) (pitagora in ABC)
AC=20 cm
BC*AD=AB*AC (aria ABC in 2 moduri)
AD=AB*AC/BC=15*20/25
AD=12 cm
aria ABC=BC*AD/2=25*12/2
aria ABC=150 cm2 (1)
cu teorema bisectoarei avem
AM/MB=AC/BC
AM/(AB-AM)=AC/BC
AM/AB=AC/(AC+BC)
AM=AC*AB/(AC+BC)=20*15/(20+25)
AM=20/3 cm
aria AMC=AM*AC/2=200/3 cm2 (2)
raportul ariilor (2)/(1)= 4/9