17.
Δ CAD (∡D=90°) AVEM:
sin DAC=co/ip
sin 60°=CD/AC
√3/2=CD/12√3
2CD=12(√3)²
2CD=36
CD=36/2=18 cm
cos DAC=ca/ip
cos 60°=AD/AC
1/2=AD/12√3
2AD=12√3
AD=12√3/2=6√3 CM
∡DAB=90°-60°=30°
Δ ADB (∡D=90°) AVEM:
cos DAB=ca/ip
cos 30°=AD/AB
√3/2=6√3/AB
√3AB=12√3
AB=12√3/√3=12 cm
sin DAB=co/ip
sin 30°=DB/AB
1/2=DB/12
2DB=12
DB=12/2=6 cm
BC=CD+DB
BC=18+6=24 cm
Raspuns:
AB=12 cm
BC=24 cm
AD=6√3 cm
