45. A=l² ⇒l=√16=4 cm
R=l/2=2 cm
46.At=l²√3=9²√3=81√3 cm²
47.Formula lui Heron
S=√p(p-a)(p-b)(p-c)
p=(a+b+c)/2=30/2=15
S=√15.(15-12)(15-8)(15-10)=√15·3·7.5=15√7
48.A=πR²=π10²=100πcm²
49.A=AB·AC·sin ∡A/2=6.8.√3/2·1/2=12√3 cm²
50.60°
51.∡A=120° ⇒∡B=∡∡C=(180-120)/2=30°
52.P=3xl=3x5=15 cm
53. Ip=6√2
ip=l√2 ⇒l= c1=c2= 6 cm
54.A=AB²=6²=36 cm²
55.A treia zi=100%-35%-20%=45%
