Explicație pas cu pas:
AB/AC=3/4 => AB=3k si AC=4k
In triunghiul ABC dreptunghic => T.Pitagora BC² = AC²+AB²=> BC²=16k²+9k² => BC²=25k²  => BC=5k
Aria ABC= h×ip/2=c1×c2/2 => h=c1×c2/ip
In cazul nostru: AD=24=12k²/5k => 24=12k/5 => 2=k/5 => k=10 => BC=50cm
AC=40cm si AB=30cm
P ABC =30+40+50=120
A=30×40/2=600cm²