Răspuns :
tgB=AC/AB⇒0,75=AC/AB⇒3/4=AC/AB⇒AC=3/4AB
in ΔABC aplic th.pit.:BC²=AC²+AB²⇔30²=(3/4)²AB²+AB²
900=9AB²/16+AB²⇔14400=9AB²+16AB²⇒AB²=14400/25
AB=√576⇒AB=24cm
AC=3AB/4=3·24/4=3·6⇒AC=18cm
PΔ=AB+AC+BC=24cm+18cm+30cm=72cm
in ΔABC aplic th.pit.:BC²=AC²+AB²⇔30²=(3/4)²AB²+AB²
900=9AB²/16+AB²⇔14400=9AB²+16AB²⇒AB²=14400/25
AB=√576⇒AB=24cm
AC=3AB/4=3·24/4=3·6⇒AC=18cm
PΔ=AB+AC+BC=24cm+18cm+30cm=72cm