teorema 30,60,90,
cateta care se opune unui unghi de 30 grade are lungimea =cu jumatatea ipotenuzei
cateta 1=20cm/2=10cm
conform teorema pitagora
Δ dreptunghic,un unghi 90 grade=> ipotenuza la patrat =suma patratelor catetelor
i²=c1²+c2²
c2²=i²-c1²
c2²=(20cm)²-(10cm)²=>c2²=400cm²-100cm²
c2²=300cm²
c2=√300cm²
c2=10√3cm²
ariaΔ=10cmx10√3cm=100√3cm²
